Create More Shrubs with Stem Cuttings

Weigela shrub, ready for stem cuttings

Plant propagation is just a fancy word for making more plants from what you have. I love to propagate the plants in my garden. To me it is magical that an entire shrub can be created from cutting six inches off the stem. Taking stem cuttings is an easy way to make more shrubs to fill in gaps in the garden or to share plants with gardening friends.

Summer is a good time to take “softwood” stem cuttings of shrubs. The term “softwood” relates to the time of year the cutting is done — usually May through July. This is the point where a deciduous shrub’s new spring growth starts to become semi-woody but still supple enough to root easily. The shrub’s stem must have new growth but be firm enough to snap. If you can grasp the end of the branch about 6 inches from the top, bend it at a 90-degree angle and it snaps and breaks off, it is ready. Depending on the plant and your comfort zone, it may not be necessary to use a rooting hormone.

The best time to take cuttings is in the early morning when the plant is turgid, not wilted from the day’s heat. Cut from the tip of stem, about 5-6 inches down, ensuring that there are several nodes. The node is the point where additional stems/branches arise but also the point in which there is a higher chance of roots stimulation. First cut above the node on the shrub and then make a second cut on the stem, just under the last node. Remove the bottom leaves and insert the cutting into water, then a rooting hormone (if going to use one), and then in the pre-moistened potting mix, about one-inch deep.

stem cutting of a weigela shrub

For small shrubs, use a small plastic container and cover the plant with a gallon size Ziploc plastic bag. Blow air into the bag to inflate it as much as possible and close it. Write the plant name on the bag and write down the plant name and date on the calendar or gardening journal.

For large shrubs, such as an oak leaf hydrangea, use an old glass fishbowl, covered, or the large plastic containers of Twizzlers.

Place cuttings in a cardboard box in the shade (the box prevents the bags from blowing over or away). Check the bags to make sure condensation developed inside. If there is condensation, it has enough moisture. If there is no condensation, open the bag, take the plastic container out, water, and put back in the bag.

It may take a few weeks to a few months for the stem cuttings to root. Check by opening a bag and gently pulling the cutting to see if there is resistance. If the cutting has rooted, start to open the bag a little bit, a few hours a day, still in the shade. If the plant wilts very quickly, it has not produced enough roots yet. Successful rooters will keep their color in their leaves; unsuccessful plants will fade or collapse.

weigela cutting in an inflated bag

Once the plant can survive outside the bag, move to a larger container. Gradually expose the plant to full sun. You may end up planting it in the garden bed in the fall because the larger the plant, the more the roots and the more likely it will survive. Plus, cool fall weather is better for transplanting than hot summer heat.

If the plant is a quick and easy rooter, you will not need a commercially prepared rooting hormone. Plants have hormones that aid in the formation of roots called auxins. The amount of auxins may vary in plants throughout the year and within the plant.  If you do not know if it will root easily or you want to increase your chances of a quick root, you can use a commercially prepared rooting hormone. In other words, it does not hurt to use a hormone. Commercially prepared rooting hormones are comprised of synthetic auxins called indolebutyric acid and/or naphthaleneacetic acid. Usually a lower percentage of the synthetic hormone is required for these softwood cuttings (1,000 ppm or .1 percent) and often comes in a white powder form. When you use the rooting hormone, put a small amount in a little container to prevent contamination that could occur if you dip the stem cutting into the original container.

Dipping stem into small amount of rooting hormone

When you are multiplying by stem cuttings you need to prevent fungal growth. Use clean plastic containers with drainage holes and bagged potting mix (not ground soil). Use tap water for watering the potting mix and for moistening the cut before dipping in the rooting hormone.  Bags, including the larger propagation chambers such as plastic shoe boxes, plastic storage containers, Twizzler containers, and glass terrarium/fish tanks, must be clean.

This month, try taking several cuttings from one shrub so if one does not root, you won’t get disappointed. Experiment, take notes, and discover the magic of plant propagation. Good luck!

Deutzia ‘Chardonnay Pearls’

Deutzia Chardonnay PearlsI have to give a shout out to a wonderful Proven Winners shrub that I have had for almost 20 years. Deutzia ‘Chardonnay Pearls’ is a small, deciduous shrub that leafs out in March and covers itself with tiny, pearl-like buds in April. From April through May, the buds open to white, bell-shaped flowers, complementing the light green leaves. When my Deutzia ‘Chardonnay Pearls’ is in full bloom it looks like a snow-capped hill. Like snow, the flowers gently fall to the ground as they past their prime, melting and disappearing within the soil.

In the summer, the 3-foot shrub provides light green color in an otherwise dark corner of the garden. Some people say the leaves are lemon-lime colored; some say chartreuse, but mine are light green (I have another true chartreuse shrub near it so I can see the difference). The species has dark green leaves and grows to 5 feet. Although the flowers are delicate, all deutzia shrubs are well-known for being pest, disease, and deer resistant.Deutzia Chardonnay Pearls 2

My plant is on the east side of the house where it receives morning sun and afternoon shade.  Although that particular garden bed has well-drained soil, high in organic matter, the plant can tolerate a wide range of soils. Hardy to zone 5, Deutzia ‘Chardonnay Pearls’ thrives despite snowy winters and dry summers. Try growing this shrub in your garden for showy spring blossoms.

Baptisia Plants Perform Well in the DC Metro Area

Baptisia ‘Lemon Meringue’ flowers up close

Blooming now in my garden are several baptisia plants, also called false indigo. Baptisia is a shrub-like plant that does well in our hot and humid summers. Recent breeding efforts have expanded the range of flower colors creating a new look for an old favorite.

I have two Lemon Meringue and two Dutch Chocolate plants. I purchase them 10 years ago as small plants and now in May, they are about 3 feet tall and blooming. They bloom in April and May and surprisingly make good cut flowers. I cut a few branches for a simple indoor arrangement and they lasted over a week. The blossoms are similar to pea flowers on tall spikes.

Although they look like shrubs in the summer, these plants are herbaceous perennials. In the fall, they produce dark brown pods that rattle and can either be left on the plant or used for dried flower arrangements or crafts. The shrubs die back in the winter and new growth emerges from the base in March.

Baptisia plants are deer resistant, heat and humidity tolerant, and drought tolerant once established.

I highly recommend these plants and if you are looking for top performers, check out Mt. Cuba Center’s 15-page report, Baptisia for the Mid-Atlantic Region. From 2012 to 2015, staff evaluated 46 selections of baptisia including representatives from 11 different species to determine which performs best in the mid-Atlantic region. Over 60 percent of the plants tested receive 4 or 5 stars. Among those, 10 superior cultivars outperformed the rest. Although I did not know it at the time I purchased my plants, they are included in the top ten.

Try growing these plants, which should be easy to find at local garden centers. They will do you proud!

Dutch Chocolate and Lemon Meringue

 

 

Growing Herbs in a Strawberry Jar

mint in strawberry jar

Mint in a strawberry jar

Growing herbs in a strawberry jar is easy — the trick is to plant herbs with similar light requirements. For full sun, try rosemary, sage, basil, thyme, oregano, or lavender. For shade, try chives, lemon balm, or parsley. Or alternatively, just one herb such as mint, which should be grown in a container instead of in the ground.

It is not necessary, but some gardeners like to insert a one- or two-inch diameter PVC pipe with holes drilled lengthwise to make watering easier. The pipe length should be one to two inches higher than the jar.

Purchase small herbs and a bag of potting mix. First take your herbs out of their containers and tease the roots apart. Sometimes you can actually tease the plant apart to get more than one.

Cover the top opening of the pipe so potting mix does not fall into the pipe. Insert the pipe into the center of the jar and add potting mix up until the first “hole” while keeping the pipe upright.

herbs in strawberry jar

herbs just planted in a strawberry jar

Push a plant through the hole, add soil on top of the roots in the jar, tamp down, and continue adding soil until the next hole. Plant each hole, in an upward spiral fashion, until you reach the top. At the top, add the last plant, which should be one that grows vertical and tall. Tamp the mix down so the soil level is a few inches below the jar’s rim. Pour water into the pipe.  If you are not using a pipe, water the top of the jar, gently. A little potting mix may become dislodged but over time, as the plants grow, everything will stay in place.

During the summer, make sure the plants are well-watered as most jars are made of terra cotta, which dries out quickly. Snip and harvest the herbs as needed.

Native Fringe Tree with Showy Spring Flowers

Recently I was in Charleston, SC, and saw many blooming fringe trees. I always thought they were Virginia natives — not southern belles.

Fringe trees (Chionanthus virginicus) bloom wispy cream flowers, like an old man’s beard. They were blooming in March in South Carolina and they will bloom later here. They prefer full sun to part shade and moist fertile soil. Their natural habitats are damp woodlands. Fringe trees are named after their sweetly scented flowers, comprised of 4 to 6 one-inch long straps. Although fringe trees are dioecious (male and female plants), they both flower. Some produce what are called “perfect” flowers (having both male and female parts). Therefore, female flowers and perfect flowers produce fruit that resemble dark blue olives. Fringe trees belong to the olive family and the birds love the fruit. These slow growing trees mature around 15 to 20 feet and are perfect for the home as specimen trees.  Try planting a fringe tree in your garden!

 

Best Phlox Plants for Mid-Atlantic Gardens

Lavelle phlox

Lavelle

Since I have been living at this house in Northern Virginia, a bed of creeping phlox has bloomed every spring without fail. The plant came with the house and we have been here for 25 years.

Phlox is a very common perennial in the mid-Atlantic area. Many gardeners –as well as butterflies– love the old-fashioned, native plant for its tall stems of summer-blooming pink, purple, or white flowers.  Phlox is actually a large genus comprising more than 60 species native to North America. There is wide variation — some plants are tall, low growing, or groundcovers, while some prefer full sun and others thrive in shady, woodland areas.

This year, before you purchase phlox for your garden, read about the recommended varieties in Mt. Cuba Center’s report. The horticulturists at the Trial Garden, Mt. Cuba Center, Delaware, completed a three-year study from 2015 to 2017. Although the report was published a few years ago, the data is still applicable. Staff tested 94 selections of eight sun-loving species and 43 selections of two shade-loving species.  For the sun lovers, they deliberately tested for resistance to powdery mildew, a fungal infestation of the foliage that creates an unsightly white powder. (This usually does not kill the plant but detracts from its beauty).

Of the sun-loving plants, within the species Phlox paniculata, top performers are ‘Jeana’, ‘Glamour Girl’, ‘Delta Snow’, ‘Lavelle’, ‘Robert Poore’, ‘Dick Weaver’, ‘David’, ‘Ditomdre’ (Coral Cream Drop), ‘Shortwood’, and the hybrid P. x arendsii ‘Babyface’.

Jeana

“Jeana,” according to the report, “is, without a doubt, the best performing phlox from the trial. This cultivar was discovered growing along the Harpeth River near Nashville, Tennessee and named after its discover Jeana Prewitt.”

Interestingly, volunteers who monitored pollinator visitations in the trial garden, noticed that ‘Jeana’s’ pink flowers received 539 visits from butterflies over 2 years. Others phlox flowers received at best 117 and lower.  ‘Lavelle’, second in place, received 117 visits indicating a marked preference for ‘Jeana’.

 

Blue Moon phlox

Blue Moon

Horticulturists also trialed shade-loving woodland phlox (Phlox divaricata) and creeping phlox (Phlox stolonifera). Their report stated that the creeping phlox was easy to grow while the woodland was more difficult. However, they conceded that their initial plants of the woodland may not have been the healthiest. The best performers of woodland phlox are Phlox divaricata and P. divaricata ‘Blue Moon.’ With creeping phlox, best performers are Phlox stolonifera ‘Fran’s Purple’, ‘Home Fires’, ‘Pink Ridge’, and ‘Sherwood Purple’.

Fran's purple phlox

Fran’s Purple

All photos courtesy of Mt. Cuba Center

Today is Sweet Potato Day

Sweet potato

Today, Monday, April 6, is sweet potato day. I find this odd because here in Virginia, one does not plant or harvest sweet potatoes at this time. So I did some digging (no pun intended) and discovered the origins of the date.

In Benton, Kentucky, there is an annual sweet potato event the first weekend in April. Apparently, the sweet potato grows well in Kentucky’s hot, humid summers. Tater Days is celebrated with a parade, a carnival, and baking and canning contests.

Sweet potatoes are botanically different from white potatoes. Sweet potatoes (Ipomoea batatas) are in the morning glory family while white potatoes (Solanum tuberosum) are in the nightshade family. Both produce tubers but sweet potatoes are planted in the summer and harvested in the fall, while white potatoes are planted in the early spring and harvested in the summer. Sweet potatoes need a long growing season, at least 4 months, and thrive in Virginia summers, much like Kentucky.

While white potato plants are started with chunks of the tuber, sweet potatoes are grown from rooted sprouts called slips. Slips may look like limp, short stems with no roots. If you order slips, plant them when the soil has warmed to at least 60 degrees and night temperatures are above 60 degrees. If it is too cold, pot them up and hold them inside near a sunny window.

Plant slips about a foot part, covering with soil up until the first pair of leaves. These plants are usually grown in the ground, in loose, well-drained soil. These plants are vines that grow several feet long so give them plenty of space. The green, heart-shaped leaves are edible (deer like them too). The plants will grow up until frost and the tubers should be harvested before the first heavy frost. Southern Exposure Seed Exchange sells slips but try any company that specializes in vegetables.

Sweet Caroline Sweetheart Red ornamental sweet potato

You may see ornamental sweet potato plants for sale in small containers at the local garden centers. These are not grown to eat the tubers, they are grown for their beautiful foliage. Ornamental sweet potato plants can have chartreuse, dark purple, bronze-red, mahogany red, or variegated cream, green, and red colored leaves. These are used frequently in containers in public spaces and gardens because the vines are ideal “trailers,” draping over containers. Since they are tropical plants, they tolerate the summer’s heat and add quite a lot of color.

Try both, they will do well in your garden.

Sixteen Seed Starting Tips

marigoldsGardeners like to start seeds indoors to get a jump start on warm season plants such as tomatoes, peppers, and melons. They also start seeds indoors to be able to grow plants that have a longer growing season than the season in which they live. Before you begin to sow seeds indoors, read these sixteen tips to have as much success as possible. If you haven’t ordered your seeds yet, here is a list of seed companies.

ONE: The sunlight through your windows will not provide enough light. Use fluorescent tubes from hardware stores or purchase special grow lights but make sure their height can be adjusted. Seedlings are grown an inch away from the light source but as they grow the light source must be able to be adjusted. Lights have to be on for 14 to 16 hours daily but you can use a timer.

TWO: Yes, you can make your own seed starting mix but why? It is easier to purchase a bagged mix made especially for starting seeds – this mix is sterile with enough porosity for seeds to germinate and push through.

THREE: Not every seed should be started indoors. Some should be sown outdoors such as cilantro, dill, carrots, spinach, radishes, beans, and peas. Look at the seed package for instructions.

FOUR: What you use as a container is partially determined by what you are sowing. For example, if you are starting a lot of tomatoes, you can use one large tray because the seeds are likely to germinate and grow at the same rate. If you are sowing a variety of plants, use many small containers because each plant will have a different rate of germination and growth. Use plastic containers with drainage holes, draining excess water into a watertight, plastic tray. These can be small plastic cups, fruit cups, or yogurt cups. Another option is soil blocking.

FIVE: Once you sow and water seeds, you need to keep the seed moist until germination because if they dry out, they are no longer viable. This is why many people use clear plastic domes but remember to remove these domes when you see the seed emerge.

SIX: Water the mix in the container so it is moist before planting the seed. It will likely be hard to get moist, it may take several waterings, letting the water drain through, and tamping down with your fingers until you can sow the seeds. Then water again to soak the seeds.

SEVEN: The most common problem is “damping-off” which is caused by a fungus that thrives in warm, moist environments that are poorly ventilated. You will see pinched stems and seedlings that fall over. There is no recovering from this so one must prevent damping off by using clean containers, fresh water, increased air circulation, and not overwater.

seed packetsEIGHT: Usually, fine seed need light to germinate while larger seeds should be buried; check the seed package.

NINE: Heat mats are only necessary if you are starting warm season seeds in a cold area. Not all plants need this and not all places in the home need extra warmth. If you are starting seeds in a very warm room in the house (maybe upstairs – heat rises) you should be fine. If you are using a cool basement, you may need a seed heating mat. However, once the seeds have emerged, they can tolerate cooler temperatures.

TEN: Always label and keep records–within weeks you won’t remember anything. Because the small containers will be close together and under the light, you may want to mark the containers with a black magic marker instead of using plant tags at first.

ELEVEN: What you will see first is not the true leaves but the cotyledons. These once were the halves of the seed. They will look like leaves but soon they will shrivel and die off. Then you should see the first set of true leaves that can begin the photosynthesis process (i.e., make its own food). Decrease watering as you see growth emerge because really the roots are now down deep in the container taking up water so the surface can look a little drier than when you first sowed.

TWELVE: If you planted too many in one container, you can transplant seedlings into other containers after you see this first set of true leaves. Alternatively, you can remove the weakest looking ones with small scissors, just cut across at the base of the soil, do not pull it out.

THIRTEEN: When to start the seed indoors under lights? First determine your average last frost date for your area. Then count backwards the number of weeks given on the seed package. For example, if I use Mother’s Day as my average last frost date then I would start Black Krim tomato seed 6 weeks prior so it would be the last week in March. In that six-week timeframe, I know that probably the last 2 weeks, end of April, beginning of May, I will have moved the seedling to a larger 4-inch pot and place outside on the deck. This period will allow it to harden off.

FOURTEEN: Some seeds have to go through a scarification process where the seed coat either has to be nicked with a file or the seeds have to soak in a container of water for 24 hours before they are sown. For example, soak morning glories in water overnight before you sow them to help the process of breaking down the seed coat and letting the water in. Other seeds need to go through a stratification process of moist, cool temperatures several months before they will germinate. These seeds can be stored in the fridge for a few months before you attempt to sow them. Seed packets should state these requirements.

FIFTEEN: The caveat to #14 is that the seed packet is small and can only offer so much information, so read more information on the company’s website or catalog, or search on the internet, or look in a gardening book in order to have as much knowledge and success as possible for that particular plant.

SIXTEEN: Often there is too much seed in a packet. Don’t think you have to sow all the seed in the packet. In fact, save some in case your initial planting does not work out, or share/swap with friends, or use next year. Most vegetable seed will be viable next year with the exception of onions and leeks.

Good luck!

Salad Burnet Graces the Garden

Salad burnet (Sanguisorba minor) is a beautiful perennial plant that also serves as both a medicinal and culinary herb. This relatively small plant grows to about 6-8 inches tall and a foot wide. It stays green above ground for quite a long time, dies back in the winter, and re-appears in the spring. The plant grows in a clump or rosette formation. The small summer flowers are very small on wiry stems — barely noticeable.

As a medicinal herb, salad burnet has astringent qualities and is used to staunch bleeding. As a culinary herb, the leaves can be added to a green salad, egg salad, herbal vinegar, butter, cheese spread, or as “lettuce” with sandwiches. The foliage can be added to lemonade and is a popular garnish for gin and tonic cocktails. It has a clean green flavor, much like cucumbers.

The foliage has a delicate, lacy appearance. When my daughter and I made a charcuterie board for Thanksgiving, we decorated the board with salad burnet. We also used the green lacy leaves as a contrast to red cranberries and white mashed potatoes.charcuterie board

I have been growing salad burnet for years, but not necessarily the same one. It does self-seed a little, just enough for volunteers to show up in odd places. I dig them up and put them where I know they will thrive. Over the years, I have learned that salad burnet prefers moist areas, in full or partial sun, depending on the amount of soil moisture. I now have a plant growing next to my cutting celery and lovage, all of which are moisture lovers.

You are not likely to find the plant in local nurseries, but you can purchase seed from online seed companies. Start seed indoors in the spring, under lights, much like starting tomato seeds. You can direct sow in the summer, but my birds always steal my seed before they germinate. Or if you have a friend who has salad burnet growing in the garden, ask for a division in the spring. Try growing salad burnet for its many uses but also as a pretty plant in the garden.

Spring Flowers: Columbine (Aquilegia)

Spring has many woodland bloomers: bluebells, dutchman’s breeches, bloodroot, yellow trout lily, and trilliums to name a few. Of these, columbine (Aquilegia spp.) can adapt to live successfully in your own garden. Columbine plants are low growing perennials noted for downward faced flowers with long, thin spurs that reflex back. These shade tolerant plants are often found in moist, woody areas.

In the mid-Atlantic region we either see the native species, Eastern red columbine, or cultivars of the common columbine. Eastern red columbine (Aquilegia canadensis) has red and yellow flowers with spurs. This native is a critical food source for the ruby-throated hummingbird in the spring. The Virginia Native Plant Society named it wildflower of the year for 1998. There are other columbines native to this continent but not to our mid-Atlantic region.

The native species blooming at Oak Spring Garden

The common columbine (A. vulgaris) has been bred to produce flowers that are single or double petaled, in shades of purple, blue, dark rose, rose, pink, white and even very dark purple to black.

Both are easy to grow from seed as long as you provide stratification–that period of cold to induce germination. If you are purchasing seed, you can provide stratification in one of four ways:

  • Place the seeds in a plastic bag with moist seed starting mix. Place the bag in the fridge for 3-4 weeks. Afterwards, you can start the seeds indoors under lights about 8 weeks before the average last frost or sow directly outside after the last average frost.
  • Sow the seeds in small plastic containers with moist seed starting mix and either put in the fridge, an uncovered cold frame, an unheated porch, or a shed where the temperature remains consistently between 35 to 45 degrees. When the average last frost date has passed, continue to grow outside.
  • Scatter seeds in your garden in the fall and let winter provide the cold stratification.
  • Sow a few seeds in a plastic gallon milk jug with about 3 to 4 inches of soil in December and leave outside, uncovered, until spring. In the spring, open the jug and transplant the seedlings into the garden. This method is called winter sowing.

Once your plants are established, they will self-sow. In fact, columbines are notorious for cross pollinating so if you want one particular color, grow only that plant. Do not mix up your seed. Mine have been in my garden for almost 20 years and are a mix of purples and blues. I know I have sowed several different types over the years, but these colors must be the hardiest.

Columbine blooming at the National Arboretum

Columbine plants are deer resistant, and the flowers attract hummingbirds, butterflies, and hawk moths. After the spring, the foliage will remain which does tend to get leaf miners but this will not kill them. Leaf miner damage just goes with the territory, there is not much you can do other than snip off the damaged foliage. The unsightly silver “doodles” on the leaves is caused by leaf miner larvae tunnelling their way through the middle of the leaves. The Eastern red columbine is supposed to be more resistant to leaf miner than the hybrids. In the winter, these plants die down and become dormant. Foliage emerges as early as February.

In our area, we have plenty of spring native plant sales so you may find small plants of the Eastern red columbine. If not, check out these seed companies for both the native species and the hybrids.

Close up of the center of the flower