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Enter your e-mail here to subscribe to Pegplant’s Post, a free, monthly e-newsletter about gardening in the Washington DC metropolitan area. Each issue lists local gardening events, recently published gardening books, articles, and tips specific to this area. Sometimes there is a giveaway for subscribers. The upcoming June 2025 issue has an opportunity to win a packet of California poppy seeds, courtesy of Outsidepride Seed Source.

Outsidepride is an Oregon-based, family-owned online seed business. They have one of the largest seed inventories in the country. They sell all types of seed: clovers, cover crops, flowers, grass, groundcovers, herbs, wildflowers, drought-tolerant, and vegetables. You can order from their website plus you can further select seeds by season, bloom color, USDA hardiness zone, height, deer resistant, houseplant, and light requirements. Clicking on a particular plant reveals extensive growing information.

Pegplant.com is an online resource for gardeners in the DC metro area. This giveaway is for subscribers of the Pegplant’s Post newsletter only so subscribe today!

May Is Dahlia Planting Time

May is dahlia planting time — when you know for sure that there will be no chance of frost. Like chrysanthemums, many people associate dahlias with the fall but dahlias can bloom from the beginning of summer to frost. Dahlia flowers are available in a wide range of sizes, colors, and shapes. Each bloom can be 2 inches across to more than 10 inches, in all colors except blue. Plants can reach one to 6 feet tall. Some plants have beautiful dark foliage instead of green leaves. Although there are 40 plus species there are thousands of cultivars. In addition, there are numerous forms such as the single, peony, anemone, collerette, star or single orchid, double orchid, cactus, waterlily, ball, and pompom.

Planting Tubers or Seed

To grow dahlias, you can either purchase tubers, start them from seed, or buy small containers of dahlias already started from the nursery. If you purchase a tuber that is a named variety you will know exactly what the plant will look like. Plus, if you purchase cultivars that have been trialed and proven to do well in this area, you will have a good chance of success. With dahlias, it is important to purchase one that is known to do well in your area.  It is best to ask for recommendations from local dahlia growers. Seed is cheaper than tubers but there is a lot of variability with plant vigor and flower color. Although the seed will grow and produce a plant with pretty flowers for the garden, the flowers may not be exhibition quality.

Tubers can be planted outside in warm soil with temperatures between 60 and 65 degrees minimum. Tubers also can be started indoors in April in containers under fluorescent lights or by the window to initiate growth. Seed should be started indoors under lights because planting seed in cold soil may retard the germination rate. Starting seed outdoors in May will only delay the time to reach blooming stage.

Caring for Dahlias

“Put the tuber in a four-inch hole and cover so that it is just peeking through. This way you can see the growth. When it grows, add more soil,” advises John Spangenberg, member of the National Capital Dahlia Society and owner of Crazy 4 Dahlias. John is a long time dahlia enthusiast who also sells tubers from his website.

Growing a dahlia plant is similar to growing a tomato plant: full sun and plenty of water and food. A dahlia can grow in less than 6 hours of sun but would not produce as many flowers. After planting the tubers, insert stakes such as tomato cages, peony hoops, or posts. In the beginning, dahlias will require plenty of water, generally one inch of water per week. Dahlias are heavy feeders and will need fertilizer throughout the summer. Seaweed-based liquid fertilizers or slow release fertilizers work well. Dahlias appreciate a leaf or straw mulch to keep the tubers cool and to prevent weeds.

Encouraging More Flowers

In the beginning of the growing season, John recommends topping the plants to encourage bushier, sturdier plants with more flowers. The center bud (not flower bud but central growth) should be pinched back. “When you see three to four sets (or pairs) of leaves, break the center top off,” explained John.

Later in the season when flower buds appear, disbud or cut off smaller, lateral flower buds to encourage the top bud to form a single, larger flower. When a dahlia flowers, there are three stems with three buds in a v-shape. When the outer two smaller buds are the size of peas they should be cut leaving the center flower bud.

“The more you cut your flowers, the more flowers you get,” said John. If you don’t cut a flower for a vase, make sure you at least deadhead them. Deadheading is cutting off and disposing flowers that are past their prime to encourage the plant to produce more flowers. For the vase, it is best to cut flowers in the morning when the weather is cool and the plant is most turgid.

Saving Tubers in the Fall

Dahlias are native to Mexico. In this area they are treated as tender perennials and may or may not come back the following year. To ensure that the plants can be grown again next year, most gardeners lift and store the tubers in October.

“In the fall when get the first frost, cut the plant a couple of inches above the ground and let sit for a week or dig them up,” explained John. “You want to have the eyes develop and swell to be able to see them well. It helps to see the eyes when dividing the tubers. You can divide in the spring or fall but it is easier to divide in the fall.”

Dahlia tubers are swollen roots. Each tuber has to have an “eye,” which is a growing point in order to grow. From that eye the stem will emerge. In May, a single tuber with an eye is planted for a single plant. In the fall, when the plant is lifted out of the ground, there will be more new tubers joined together in an area called the crown. The “eyes,” or viable growing points, are in the crown. This can be stored as is or divided to create more plants.

John uses vermiculite in a box to store his tubers but there are many methods to store tubers. He finds vermiculite works best because it absorbs and releases moisture. Tubers should be in the coolest place in the house where there is constant temperature such as a crawl space or basement or a closet next to the outer wall of the house.

Because they are native to Mexico, one would think that dahlias would be easy to grow here with our sunny, warm summers. In fact, dahlias are native to a mountainous region in Mexico with more wind, less humidity, and cooler temperatures. Thus dahlias grow very well in the Pacific Northwest but have some difficulty in the mid-Atlantic. They need quite a bit of water, yet as heavy feeders, the rain can leach the nutrients. Plus the humidity can encourage disease. “In this area, we have issues with slugs, earwigs, rabbits, groundhogs, and deer,” said John. “Plus we have noticed that Japanese beetles prefer white and yellow flowered dahlias.”

Selecting Dahlias for Washington DC Metro Area

To choose a dahlia that performs well here, look to the National Capital Dahlia Society for recommendations. A branch of the American Dahlia Society (ADS), the National Capital Dahlia Society is comprised of dahlia enthusiasts and breeders who meet on a regular basis. They have events and shows that may be open to the public to see blossoms and to be able to ask experts questions in person.

The Society manages a trial garden at the Agricultural History Park in Derwood, MD. “The display garden is a trial garden to test new introduction from across the country to see how they do here. We look at bloom quality and plant vigor and report this to the American Dahlia Society,” said John.

To learn more, check out the National Capital Dahlia Society website which also has a calendar of events. Attend a show, usually in the fall, to see the variety of flower colors and shapes and to be able to speak with experts.

Mosquito-Repelling Plant Myths

There is a common myth that planting lemongrass (Cymbopogon citratus) in the garden will prevent mosquitoes. Lemongrass is a stunning specimen plant and a fantastic culinary herb, but it will not repel those nasty pests. Although it is true that the foliage contains an essential oil which mosquitoes do not like, a person would have to cut open or bruise the foliage to release the oil and apply the oil all over the skin. Lemongrass has very sharp foliage and applying an oil directly on the skin could cause a reaction. Plus, you would have to cover every exposed inch, including the face, as mosquitoes can find an unprotected spot the size of a dime.

So don’t be fooled into purchasing lemongrass in order to have a pleasant, insect-free party on the patio. Likewise, don’t think that “mosquito” plant, a type of scented geranium (Pelargonium graveolens citrosa), peppermint (Mentha x piperita), lavender (Lavandula spp.), catnip (Nepeta cataria), citronella lemon balm (Melissa officinalis citronella), and lemon eucalyptus (Corymbia citriodora) will do the trick. All of these may have an essential oil in the foliage that mosquitoes find repellant, but the leaves would have to be crushed, wiped all over the body, and potentially cause a skin reaction.

It is best to spray with DEET or other EPA-approved repellants that have been formulated for use on bare skin. Another alternative is to wear permethrin treated clothing (but even then you would still have to apply something on body parts not covered by clothing). Here are more tips to control mosquitoes on your property.

Tips for Growing Peppers in the DC Metro Area

peppers in container

peppers combined with flowers in a container

Peppers are easy to grow from seed, but you also can purchase small plants at the local garden center in the beginning of the growing season. If you grow peppers from seed, you can grow a wider variety than what is available at the garden centers. All peppers are grown the same way, they have the same cultural requirements. There are almost 30 species of Capsicum, but in the mid-Atlantic area, we tend to grow three: C. annuum, C. chinense, and C. frutescens.

Within C. annum, there are many varieties and hybrids. Bell peppers are large and sweet, maturing in a red, yellow, or green color. These do not have capsaicin, the compound responsible for heat, due to a recessive gene that eliminates the capsaicin. Other peppers without capsaicin are the Italian frying peppers, Jimmy Nardello, Giant Marconi or Marconi, and banana or yellow wax peppers. C. annuum also includes hot peppers, also called chili peppers, which have capsaicin.

Capsaicin is primarily concentrated in the veins, ribs, and seeds. Removing these is one way to reduce the heat. Capsaicin is an oil which is why drinking water when you have eaten a particularly hot pepper does not help get rid of the burn. Instead, drink milk or eat yogurt, a banana, bread, pasta, or potatoes.

The Scoville scale is a measurement of the heat of a chili pepper recorded in Scoville Heat Units. It is based on the concentration of capsaicinoids among which capsaicin is the predominant component. This range is 0 to as high as 2,693,000 (Pepper X according to the Guinness World Records in 2023 whereas previously the Carolina Reaper was the hottest). Sweet peppers are 500 or less and include the bell pepper and the pimiento.

The C. chinense species is the habanero type of pepper – a type of chili pepper Native to South and Central America that includes habanero, scotch bonnet, and ghost pepper.

The C. frutescens species is another chili pepper native to South and Central America that produces small fruit that tend to grow upright. C. frutescens includes the tabasco pepper and the colorful ornamental varieties.

If you are really diving deep into peppers, there are two other species you can try to grow but likely you will have to start from seed as the plants usually are not available in this area.

Mad Hatter, a baccatum type sweet pepper with a unique shape that will turn red at maturity

The C. baccatum species has a wide variety of peppers, from sweet to hot, from South and Central America. Many are beautiful with unique shapes. These include bishop’s crown, Brazilian starfish, lemon drop, and the “aji” peppers (have “aji” in their name although not all aji peppers are in this genus).

The C. pubescens species has apple-shaped fruit and hairy foliage. They can be mild or very hot. Native to Peru and Bolivia, popular varieties include rocoto, manzano, and locoto.

Starting Peppers from Seed

If growing from seed, start indoors under lights about 4 to 6 weeks before the average last spring frost. Sow seeds about ¼ inch deep. They like warm rooms to germinate so if you are doing this in your basement, you may need a heating mat. Peppers are slow to germinate, the hottest peppers are the slowest. It could take more than a week to see anything. Direct sowing seeds is not recommended because the soil in May will be too cold.

sweet peppers in a container

In May, after frost has past, night temperature are consistently above 50 degrees, and soil temperatures are at least 60 degrees, move the plants outside or plant the ones you purchased from the garden center.

If you are moving your seedlings outside, remember to harden them off by gradually exposing them to light and the winds. If there is an unforeseen cold night, cover with a cloche or a 2-liter plastic soda bottle with the end cut off.

Transplanting into the Garden

Don’t rush to plant your peppers. They need warm temperatures so this could be June (or if you live in Virginia, after the dogwood blossoms have fallen). Peppers do best in soil with a pH of 6.5 to 7. Make sure you amend the soil with compost; they do not want too much clay. They need good drainage. Peppers also can be grown in raised beds or in containers that are at least 5 gallons with drainage holes. Place in full sun, at least 8 hours of sun a day, spaced at least 18 inches apart (from central stem to stem). They do not like to be crowded. Make sure your hose reaches them.

Unlike tomatoes, you don’t plant them as deep as possible. Plant the transplant so that the shoots are at the soil line as they were before transplanting.

Peppers are susceptible to sunscald which occurs on the fruit that has been exposed to intense direct sunlight. This could happen when you first plant them but will not kill the plant.

Usually, peppers do not need to be staked, nor do they need to be pruned.

Growing Peppers in the Summer

Peppers optimal temperatures for setting fruit is 65 to 85 degrees. However, the flowers can drop (i.e., not produce fruit) if the temperatures are above 90 degrees during the day and 75 degrees at night.

Jimmy Nardello, a sweet frying pepper

Peppers need fertilizer but withhold it when the plant starts to flower. A slow-release organic fertilizer with more phosphorus and potassium than nitrogen is best. You can use one especially formulated for tomatoes.

Like tomatoes, peppers can get blossom end rot. To prevent this, make sure the soil moisture is consistent, not varying widely between very wet and very dry.

The small fruit varieties do better in the mid Atlantic’s hot and humid summer than the large fruit varieties.

They fruit up until frost so if it is just one night of cold weather, you may be able to cover for the night to extend the harvest season. If you are expecting a freeze, harvest the mature ones.

Harvesting and Eating Peppers

You need to know your varieties’ mature stage fruit color. Although all peppers may be eaten in the green stage, there is more flavor and vitamins in a ripe, colored up pepper.

Temperature influences color on the pepper. Purple pigment develops under cool temperatures so if you see purple streaks on peppers, it is because the temperature is too cool (maybe in the fall). The purple color does not affect the flavor. However, that is why it is difficult for gardeners in the mid-Atlantic area to grow solid purple varieties – it is just too hot in the summer.

red and black ornamental peppers with dark foliage

When picking chili peppers, you may want to wear gloves as the capsaicin may irritate the skin. After cutting and preparing in the kitchen, wash your hands with soap afterwards and do not touch your face or eyes.  Remember that capsaicin is primarily concentrated in the veins, ribs, and seeds so you can reduce the heat in a chili pepper by removing these.

Peppers dry well and can be ground or crushed. Wash the pepper and either cut and leave open on paper plate inside the house or leave whole (but whole will take longer to dry). Often gardeners will string up the whole peppers to hang in the kitchen. Or dry the peppers in a dehydrator, the oven, or outside in the sun. Dried peppers have more flavor and heat.

Saving Pepper Seed

If you want to save pepper seeds, make sure the plant is an open-pollinated plant, not a hybrid. Peppers have perfect flowers (both male and female parts) therefore they can pollinate themselves and do not need bees. However, bees do visit peppers and can cross pollinate the peppers in your garden and with peppers in neighbors’ gardens. This cross pollination occurs within a species. If you grew more than one variety, such as a sweet and a hot in the same genus (C. annum), be aware that bees may have cross pollinated them. Therefore, if you saved sweet pepper seeds and grow the seeds the next year, the resulting fruit could be hot, not sweet. To prevent cross pollination, you would have to separate your varieties of one species by 300 to 1600 feet or grow different species.

To save seeds, simply slice open a very mature pepper and remove the seeds. Place the seeds on wax paper to dry inside the house. Seeds are dry if they snap when you bend them. When dried, put in a container, seal, and label. Store in a cool, dark, and dry place.

You will get good germination rates from saved seeds for about 3 years.

Final Note

The mid-Atlantic units of the Herb Society of America host a Chili Celebration every October at the U.S. National Arboretum in Washington DC. This is a free event on Saturday, October 11, 2025, in the afternoon. The Units come to the National Herb Garden and set up tables of peppers to taste as well as products made with chili peppers plus a lot of information on growing peppers. The National Herb Garden also has pepper plants that are fruiting at this time. Yes, some of these are hot so we also provide milk and bread. See you there!

Yes, Virginia, Tarragon Can Grow Here

Tarragon re-emerging in April

Tarragon is one of my new culinary herbs in my Virginia garden. It took a couple of tries to figure out its happy place. I had grown a few plants before in different locations but they never reappeared in the spring. This time, the tarragon that was given to me last year is back! It must be happy with full sun exposure in a well-drained area.

A member of the Asteraceae (aster) or Compositae family, tarragon, Artemisia dracunculus, is cousin to the other artemisia plants: mugwort (A. vulgaris), wormwood (A. absinthium), and southernwood (A. abrotanum). The term “dracunculus” is considered a corruption of the French “estragon,” which means little dragon. This refers to the plant’s brown, coiled roots, similar to serpents.

Tarragon in the summer

I have French tarragon, Artemisia dracunculus var. sativa, the preferred culinary variety. French tarragon has anise-flavored leaves (like licorice). An herbaceous perennial, tarragon has green, narrow leaves and woody stems. It dies back in the fall but is one of the first to emerge in early spring, growing to about 2 feet high and wide in the summer. Hardy to zone 5 (although every reference book gives a different number), it is not a long-lived perennial and should be propagated every few years. The plant is sterile so it is propagated by division or stem cuttings. Don’t be fooled into buying tarragon seed packets. They can’t possibly be the flavorful variety, sativa. More likely they are Russian tarragon seeds, Artemisia dracunculus, which has inferior flavor but can still be grown as a plant in the garden.

Tarragon is an old culinary herb that has been used for several thousand years in the Middle East and Europe. It is one of the few culinary herbs that has no significant medicinal use. When Thomas Jefferson was in France, he enjoyed the extensive use of tarragon in French cuisine. Assuming it was propagated by seed, he searched for the seed in the colonies and was not able to find it. Eventually Bernard McMahon sent him a shipment of roots. The first time Jefferson planted tarragon at Monticello it failed but he tried again in different locations until he too found tarragon’s happy place. He then distributed the plant to colleagues. In 1809, General John Mason wrote to him and said “has flourished well in the open air and will in spring afford plenty of slips.” Mason no doubt discovered that tarragon likes plenty of air circulation.

Interestingly, the flavor of tarragon varies depending on how it is used in the kitchen which is why it is so versatile. If I pick a leaf off the plant and chew it, there is a zingy, refreshing flavor like a Peppermint Patty. It slightly numbs the tongue. If I cook with it, the flavor becomes a mellow zingy like black pepper.

Tarragon leaves are used in sauces, vinegars, fish, chicken, spring vegetables, eggs, salads, cheese, cold potato dishes, and fruit such as peaches, melon, apricots and cherries. It is the ingredient in fines herbes and béarnaise sauce. Because of its delicate flavor, it is best to use fresh leaves and to add towards the end of the cooking period so they do not become bitter and overcooked. Because the leaves do not retain their flavor when dry, many people preserve tarragon in vinegar, which also can be used as vinegar for salad dressings.

Don’t Throw Out Your Easter Lily!

Easter lilies (Lilium longiflorum) are bulbs that have been forced to bloom during Easter. If you are given one as a gift, keep it in the house in bright, indirect light. Place it in a room with cool temperatures, 60 to 65 degrees, away from drafts and heating vents. Make sure the container has drainage holes. If it came in a decorative foil, remove the foil to allow the water to drain or cut the bottom out of the foil. Keep the soil consistently moist.

Pinching off the yellow anthers prevents pollen stains and makes the blossoms last longer. Once the flowers are past their prime, remove them.

Easter lilies are true lilies, hardy to zone 4. Here in the DC metro area, you can put your plants in your garden in May after the last frost. Plant them in full sun, in well-drained soil. Plant them at the same depth as they were in the pot. Ideally 3 inches deep with 12 to 18 inches between plants. Treat them like perennials — leave the foliage on until eventually the plants become dormant for the winter. In the spring, fertilize with a slow-release balanced fertilizer or use an organic fish fertilizer.

It may take a year or two for the bulbs to bloom again. However, they will not bloom at Easter, they will bloom in the summer. In nature these are summer bloomers, like other garden lilies.

Twenty-One Tips for Growing Tomatoes Successfully

By now you should have started your tomato seeds indoors under lights. This is just if you want a head start of course, it is not necessary. You can also purchase tomato plants but be aware that the night temperatures are still cold for them to be out in the garden now. They prefer warmer weather. Waiting to plant tomatoes until the beginning of May or Mother’s Day will give you the best results. For tomato success, read these twenty tips for growing tomatoes in the Washington DC metro area.

First, know what you grow. Tomatoes have determinate or indeterminate growth habit. Determinate types produce fruit at the end of the branches so most of the crop ripens at one time and you will have one or two harvests per growing season. This is advantageous for canning. The determinate types are more compact and are better for containers than the indeterminate tomato plants; however, you may still have to stake the vines or add a trellis. Indeterminate plants produce fruit along the branches so you can pick tomatoes all season long. They can be large, vining plants; a support system such as hoops or stakes should be used.

Sun Dipper, from PanAmerican Seed Handpicked Vegetables.

2. Tomatoes come in many sizes, shapes, colors, and flavors. Grow what you like to eat or use in the kitchen. For example, determine if you prefer to use tomatoes for salad, snacking, pasta sauce, sandwiches, etc. There are more specialized varieties for specific uses such as the Sun Dipper pictured to the right which is elongated to make it easier to hold while dipping into a dip.

3. If you are limited to containers, grow the determinate type and use a container at least 5 gallons large with drainage holes or an Earthbox. Or look for varieties especially bred for containers such as window box types (usually these will be the small, cherry types).

4. Determine if growing an heirloom plant is particularly important to you. Heirlooms may be tastier, and seeds can be saved for next year, but these plants may be more susceptible to diseases. Hybrids are often bred to be disease resistant. However, if you save and sow the seed next year, the plants may not have the same traits as before. Seed catalogs and packages often have letters after the plant’s name to indicate disease resistance. For example, F is for fusarium, V for verticillium, LB for late blight, TMV for tobacco mosaic virus, and N for nematodes.

tomato

Early Girl gives you fruit earlier than most other tomato plants, photo courtesy of Ball Horticultural Company

5. Days to maturity is the number of days it will take on average for a transplant to produce a tomato (fruit) when planted in the beginning of the summer. It is not the number of days from seed. This varies quite a lot with tomatoes from plants with a lower number of days which will provide an early season harvest, to mid-season, to those with larger numbers, resulting in a late season harvest in late summer. If you have the space and want tomatoes throughout the growing season, you can plant early, mid, and late season plants.

6. If starting from seed, sow seeds about a month before average last frost date (Mother’s Day here). Start inside under lights. When the seedlings produce a set of true leaves, you can pot up the plant into a larger container and put outside for a few hours a day. Gradually introduce seedlings to more daylight and more time outside in order to harden off before putting in the ground. Hardening off is the process of acclimatizing seedlings to higher light levels, cooler (than your home) temperatures, and breezes so they can withstand being outside. Here is a link to tips for starting seeds indoors.

7. At first the nighttime temperatures may be too cold (forties and below) to leave these transplants outside so you may have to bring the pots inside for the night.

8. Seedlings and transplants in the spring may develop purple tinged leaves which means cool temperatures are preventing phosphorus absorption. In the summer, when it gets warmer, they will grow out of this so no need to do anything.

tomato

The purple coloring on Indigo sun tomato is intentional, it is a higher level of anthocyanins, which is healthy for you, photo courtesy of Ball Horticultural Company

9. Tomato plants need at least six hours of sun and like warm soil, which is why it is best to put the transplant in the ground after Mother’s Day. If you plant them in cold soil, they will sit, unhappy.

10. Tomatoes like fertile, well-composted soil, not clay. In this area, you may have to amend your garden bed with compost. In the spring, a raised bed and a container will have warmer soil than the ground.

11. When nighttime temperatures are in fifties and the transplant is hardened off, plant in ground. For the indeterminate types, insert staking or hoops immediately after planting. Make sure you have spaced your tomato plants so there is a minimum of 2 feet apart for air circulation (to decrease a pathogen’s ability to spread).

12. Tomato stems will develop roots if covered with soil. Some gardeners will bury as much stem as possible to encourage root production. The theory is that if there are more roots, the plant will be able to take up more water and nutrients. Some people lay the transplant down on the ground, horizontally, burying the stem, but leaving 1 to 2 set of leaves above ground. Some people plant vertically, but very deep, leaving 1 to 2 sets of leaves above ground. Before you submerge the stem, strip off the leaves and little branches that would be underground.

13. A lot of gardeners add calcium in the form of crushed eggshells to the soil or 1/4 cup of lime before planting to prevent blossom end rot. If you do not do this, then pick a fertilizer especially formulated for tomatoes because it should have the added calcium.

14. In the beginning of the summer, mulch with straw, leaves, or compost to prevent weeds and to keep a constant level of soil temperature and moisture. Try Maryland’s Leaf-Gro; do not use composted manure.

15. Tomatoes will need to be watered so make sure a hose or watering can is available. Water the soil, not the plant, and water in the morning to decrease possibility of fungal disease. It isn’t that tomato plants need a lot of water, it is that the soil moisture must be consistent, and not fluctuate often. Mulching helps with this.

tomato

Think of how much water, sun and fertilizer it will take to produce this large slicer, Beefmaster. Photo courtesy of Ball Horticultural Company.

16. In mid-summer, tomatoes will need to be fertilized, especially if grown in containers. Espoma has organic Tomato-Tone and Neptune’s Harvest has a Tomato and Vegetable Formula.

17. To obtain fruit, temperatures must be above 55 degrees at night but temperatures of 75 or higher will inhibit fruit set and may cause blossoms to drop. However, there are heat-tolerant varieties.

18. Tomatoes are wind pollinated. Some gardeners hand-pollinate with a paintbrush if they feel the plant is not setting fruit. All the more reason why there should be good air circulation. Harvest frequently to encourage plants to produce fruit.

19. Pruning is optional, but only indeterminate plants should be pruned. Pruning here refers to removing the side shoots or suckers. Some gardeners do this to increase or to have more uniform fruit size and to help tomatoes ripen faster. It will not increase the number of tomatoes. If prune, start when plants are about 2 feet tall and suckers are small. Do this when the plant is dry, not wet from rain.

20. If possible rotate crops to prevent soil-borne diseases. If your tomato plants are having problems, check out the Virginia Tech Extension site on growing tomatoes, tomato diseases, and tomato pests; and the University of Maryland Extension site on tomato diseases, pests, and nutritional issues, growing tomatoes, and tomato topics; or contact your local extension agent.

21. Pick the fruit when it begins to color and bring inside. Ripen at room temperature and do not put in the refrigerator. This also prevents animals from eating the fruit before you do.

Mukgenia: A Crimson Pig Plant for the Garden

Last year, when I attended the Fling at Puget Sound, I received a plant that was new to me from Little Prince Plants (thank you Little Prince for donating many plants to the Fling attendees). I dutifully packed it in my suitcase and planted it in my Virginia garden as soon as I got home. I am happy to announce it survived both the trip and this past winter. Although it is hardy to Zone 5, you just never know. Now in April the foliage is emerging, promising great things to come.

Developed by Terra Nova Nurseries, Mukgenia NOVA® ‘Flame’ is an intergeneric cross between two genera in the Saxifrage family: Mukdenia and Bergenia. The name “mukgenia” comes from “muk” from Mukdenia and “genia” from Bergenia.

Bergenia is an herbaceous perennial that you may know as pigsqueak. It thrives in shady conditions, in moist soil high organic matter. These plants are known for their large glossy leaves; spring-blooming, pink flowers; and dramatic red/bronze fall color. Rubbing the leaves together produces the sound of a pig squealing.

Mukdenia ‘Crimson Fans’ also is an herbaceous perennial known for large, ragged leaves that look like half the leaves were dipped in red paint. It too blooms white flowers in the spring but not as pretty as Bergenia. However, its fall color is gorgeous – a solid mahogany red plant.

Mukgenia NOVA ‘Flame’ combines the pink flowers of Bergenia with the interesting foliage of Mukdenia ‘Crimson Fans.’ The foliage is ragged, as if the edges were torn by hand. Many leaves have dark red edges. Hardy to zone 4, this clumping plant grows to about 8 inches tall, blooms in the spring and then exhibits great red fall color. Although the foliage is thicker than Mukdenia, this is not a drought resistant plant. It likes shade, and moist but well drained soil high in organic matter.

I am looking forward to this new addition to the garden but does anyone know if it still squeals like a pig?

Happy St. Patrick’s Day! Enjoy Your Shamrock Plants

Happy St. Patrick’s Day! Although the shamrock plant looks like a three-leaf clover it is actually a species of Oxalis. These are commonly sold as St. Patrick’s Day gift plants but they make great houseplants and garden plants.

The plants can have either green or burgundy foliage. The small flowers rise high above the leaves with five white or pink to white petals. Most people grow them as houseplants but they can be grown outdoors in the summer here in Virginia. Because they are small, it is best to grow them in containers (off the ground level) for better viewing. These are great to plant at the base of a large container that has other flowers to hide bare stalks. Or combine a burgundy foliage shamrock with a green plant like lemon verbena in a container for contrast (just eat the lemon verbena, not the shamrock).

Shamrock plants grow from rhizomes called pips which can rot if overwatered so it is best to let the soil dry out a little between watering. Eventually the plant will go through a dormant period and produce more pips that can be dug up for more plants in the fall.

In the house, the plant is best grown in indirect light with cool temperatures. Usually it is only after you purchase the plant that you learn of its charm. The leaves move up and down every day. In the daytime, at maximum light, the leaves are horizontal or open. By nightfall, when light levels are reduced, the leaves bend down almost as if the plant is wilting. Don’t worry, this is normal and does not mean that you have to water.

Shamrocks are beautiful houseplants but there is one caveat: they do not combine well with pets. Oxalis contains a high level of oxalic acid, which can be poisonous.

Growing Ginger, Turmeric, and Lemongrass

lemongrass

Bunch of lemongrass culms wrapped in plastic

Every year at this time, I visit a local Asian supermarket and pick up a few turmeric and ginger rhizomes and a couple of lemongrass stalks. For a few dollars, you can grow these tropical herbs for the summer. It is important to start early inside as ginger and turmeric have long growing seasons. It can take 8 to 10 months for the plants to fully develop in order to be able to harvest the rhizomes. Fortunately, they do not need the type of light structures you use to start seeds indoors.

Visit your local Asian supermarket and you will see bins of turmeric, ginger, and lemongrass. If possible, purchase organic ones but of these, I only see organic ginger in my stores.

ginger

Organic ginger rhizomes in bins

For the ginger (Zingiber officinale), pick rhizomes that are as healthy, disease free, and as plump as possible. Ginger is a rhizome, an underground swollen stem. It has eyes, like a potato, so make sure you purchase a piece with several eyes. It is best to purchase organic ginger as regular ginger may have been sprayed with a growth inhibitor. Regardless, soak the rhizomes in water for 24 hours before you plant to remove any chemicals.  Use a plastic container with drainage holes. It is best to start with a small container, just large enough for the rhizome to fit. Think of these as starter containers. Fill with potting mix (I use commercially prepared potting mix). Plant only 2 inches deep, and plant flat or horizontally.  Keep soil moist but not water-logged until you see the foliage emerge. It can take a long time, even a month, so don’t give up hope. Because the watering is a little tricky — too much and they rot, too little and they dry out, you may want to pot up one rhizome per container. That way, if one does not make it, you still have the others. These will not need light until the foliage emerges. But they will need warmth so don’t place the containers in your basement or garage.

turmeric

Turmeric rhizomes in bins

For the turmeric (Curcuma longa), plant the same way as above. I never see organic turmeric in the supermarket so I buy what there is in the bin. I also soak them in case they were sprayed with a growth retardant (it certainly cannot hurt).  Again, best to not put all your eggs in one basket, plant one per container so if one rots, you will have the others.

Lemongrass (Cymbopogon citratus) is a little different in that it does not take that long to grow in order to be able to cut the stalks to use in the kitchen. I start them in March because I am buying all of my tropical herbs at the same time but you can start them later. Lemongrass is a true grass.  The foot-long stalk you purchase from the grocery store is called a culm. The entire stalk was cut to make it easier to handle so you are buying the bottom foot of the stalk with the base and maybe a rootlet at the base.  Look for culms that are as plump as possible and not dried out. No need to soak the night before, just plant in the container with drainage holes with potting mix. These also will root if they are in a container of water but make sure you change the water every few days.  One culm can grow to be a large 3- to 4-foot-tall plant so for my family of four I only need one but I buy several in case one does not root. If I start mine in March, I can probably start to cut and harvest in the summer, up until frost.

lemongrass

Lemongrass is relatively cheap

In May, when the evening temperatures are consistently warm, I transfer the plants outside. I put them on my deck in the shade first for them to adapt to the stronger sunlight (shade for them is stronger sunlight than what they received indoors). Then gradually I move them to larger containers and more sun. The lemongrass is moved to a full sun location. The turmeric and ginger can take part shade. I prefer to leave mine in containers because it is easier to harvest in the fall. They will not overwinter in the DC metro area. Fortunately, they are relatively easy to purchase every March and can make interesting gift plants as well. If you are really want to start a conversation, try growing the ginger and turmeric as houseplants!