Category Archives: plants

General’s Choice of Trees and Shrubs is a Wise Choice for the Mid-Atlantic Gardener

 

Spring is the season for plant sales in the Washington DC area. Every weekend there are plant and garden sales, garden parties, workshops, tours, and lectures. I look forward to these annual events just as much as I look forward to seeing the cherry blossoms. One of the more interesting plant sales is Mount Vernon’s Historic Plant and Garden Sale in Virginia. This year, the month-long sale runs from Saturday April 21 to May 20, 10:00 am to 6:00 pm (members can attend the preview night on April 20). The plants are located outdoors, just outside the Mt. Vernon main gift shop, and admission tickets are not necessary. Gardening accoutrements such as tools, books, mugs, note cards, and gift items also are available. Staff horticulturists, easy to spot by their bright green shirts, are available to answer gardening questions on Wednesdays and Sundays from 1:00 to 2:00 pm.

“At length my dear Marquis I am become a private citizen on the banks of the Potomac, & under the shadow of my own Vine & my own Fig-tree.”

What sets this plant sale apart from other local sales is provenance. The Mt. Vernon horticulturists propagated most of the plants that are for sale from the plants that are grown on the George Washington’s estate. There is a wide assortment of vegetables, flowers, herbs, trees, and shrubs. Of note is the General’s Choice Collection. Staff grew ten trees and shrubs representative of those that were grown by George Washington: three types of boxwood (American, English, and tree), two edibles (pawpaw and fig), tulip poplar, southern magnolia, redbud, dogwood, and red maple. The General’s Choice Collection has distinctive tags and can be grown easily by gardeners and homeowners in the mid-Atlantic area.

In addition, the Mt. Vernon horticulturists collected, cleaned, and packaged heirloom seed from plants grown on the estate. The beautifully designed seed packets make great souvenir gifts, easy to mail. The proceeds from the plant sale support the historical museum and gardens. Every time someone purchases a plant or a seed packet, George Washington’s legacy as a gentleman farmer lives on.

“Planted all my Cedars, all my Pawpaw, and two Honey locust Trees in my Shrubberies and two of the latter in my groves – one at each ‘side’ of the House and a large Holly tree on the Point going to the Sein landing.”

Photos courtesy of George Washington’s Mt. Vernon

Best Phlox Plants for Mid-Atlantic Gardens

Lavelle phlox

Lavelle

Despite its tendency to get powdery mildew, 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. They 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

Growing Potatoes the Easy Way: Containers on the Deck

dandelionThis year I was given two types of seed potatoes: Harvest Blend and White Superior. I have grown potatoes before in my Virginia garden and they were very tasty. This year, I am going to grow these potatoes in fabric containers called Smart Pots. Any fabric container or even a plastic container with holes for drainage will do, I just happen to have a few large Smart Pots.

Potatoes are in the same family as tomatoes and eggplants but gardeners start growing them in the spring, as opposed to their warm-season cousins.  Although you hear that potatoes are started on St. Patrick’s Day, that might only be true for the Irish. It does not always work for gardeners in the Washington DC area. We just had snow so I waited until this past weekend when I was closer to my last average frost date. I have read that the time to plant potatoes is when dandelions are blooming; sure enough, my dandelions were blooming this past weekend.

Some of the independent garden centers will sell a few varieties of potatoes but you get a much wider selection if you contact mail order companies. In fact, there is tremendous diversification of the tuber itself:  there are white, blue, red, purple or gold colored tubers–round, gnarly, slender, large or small.  In terms of cooking, tubers can be mealy like a Russet (good for baking but disintegrates in a stew) versus waxy like a Yukon Gold (holds its shape). The tubers vary in maturation days, there are early, mid, and late season varieties, thus extending the harvest from June to August. Interestingly, the foliage, that is, the above ground part, does not vary. The plant grows to a few feet tall, flowers, and dies, signaling the time to dig up and harvest the mature tubers.

Planting

To grow potatoes, purchase “seed potatoes,” which are not true seeds but the “starter” tubers one plants in the soil. It is best to start with seed potatoes that are certified as disease-free, instead of planting a grocery store potato. The shoots arise from the “eyes” and additional tubers appear along these shoots as they grow. Seed potatoes should be the size of an egg with at least two eyes. If the seed potato is this size already then plant the whole thing, eyes up. If the tuber is large, can cut into sections, each with at least two eyes. I have read differing opinions about whether you should let the cut end callous (to prevent disease); it seems some people cut and plant while other cut, callous, and then plant.

I planted my potatoes in two Smart Pots, which are ventilated fabric containers (no need to poke holes in the bottom). This is a great way to grow potatoes if you do not have a lot of land, if your garden soil is too compacted, or if you want to encourage kids to get involved. For potatoes, use at least a 20-gallon size Smart Pot with at least a 15-inch height.  Estimate 4 plants in this size and more in larger sizes.  I spaced mine about 6 inches part so I planted four Harvest Blends in the medium container (foreground in photo) and 5 White Superiors in the larger pot (background in photo).

I used potting soil that already had a slow-release fertilizer.  Because potatoes are heavy feeders, I will supplement with a liquid fertilizer later in the season.

I poured 3-4 inches of the soil in each container, watered, placed the potatoes on top, eyes up, added 3 more inches of soil, watered again, and inserted a plant label. I rolled down the sides so they would not turn inward and prevent rain from reaching the plants.

Growing

One advantage to containers is that you can place them anywhere, a deck, a porch, a driveway, even on grass. Another advantage is that you don’t have to worry about crop rotation if you have been growing tomatoes, peppers, and eggplants in the garden. My containers are in full sun on the deck so I can easily keep an eye on them. Because potatoes are susceptible to Colorado potato beetles, I have to be able to easily check the underside of leaves for the yellow/orange eggs.

Potatoes require an inch of water a week so I need to be able to water easily and often, which I can do with a hose on the deck. However, the foliage is susceptible to fungal diseases so I will water by putting the hose nozzle into the bag, not spraying the foliage and not watering in the evening.

In a few weeks I will have to “hill” the plants. The new tubers grow up from the seed potato. As the shoots grow (now stems), and more tubers appear, these new tubers have to be covered with soil. Tubers exposed to light become green and bitter.  (This also is a tip for storing store-bought potatoes, keep them out of light in a cool place but not in the fridge).  When the stems have grown about 8 inches, I will add about 4 inches of soil and repeat the process again, unfolding the sides as I add more soil. This process of adding soil is called “hilling.”

Harvesting

In early summer, when the plants flower, I can harvest immature tubers by putting my hands in the soil and pulling egg-size tubers out (leaving smaller ones in). This immature stage is what we buy as “new potatoes” in the store. New potatoes have a very thin skin and do not keep. They have to be eaten soon and usually they are boiled and mixed with parsley, chives, and butter.

In mid-summer, probably June, the potatoes will have matured. When the leaves yellow and die, I will stop watering, wait two weeks, and then dump the container. I will dump the soil on a tarp. I can either use the soil to start a new garden bed or put back in the containers to plant bush beans.

Chitting

One term that comes up with potatoes is chitting, which is common in England but not so much so here. Chitting is the process of “pre-sprouting” the tuber before planting to give the plant a head start, much like starting tomatoes under lights in the house before May. Chitting affords an early harvest but takes space and time.

I did not chit my potatoes for two reasons. By the time I received them they had already started to sprout. The tubers were small and slightly shriveled. They must have been in a place that was too warm. But if I had purchased tubers, I probably would not chit because I do not have a need to have potatoes a few weeks earlier. Plus one has to consider the space this would take and available windows.

If you are interested in chitting, place your tubers eyes up in an egg carton. Put next to a window in a warm place (the usual heated house). The type of grow lights you use for starting seeds are not necessary. After they have sprouted (like your old potatoes in the vegetable bin), you can plant them outside. If the tubers are large, cut into pieces the size of an egg with at least two eyes.

I am looking forward to growing potatoes in Smart Pots this year — freshly grown potatoes taste better than store-bought potatoes.

Snowdrops: From Simple Flowers to Complex Collections

galanthusThe common snowdrops are popular, spring blooming bulbs that are easy to grow. After planting the small bulbs in the fall, in masses or drifts for the best effect, you will be rewarded with small, white bells in the midst of winter. Here in the mid-Atlantic area, the common snowdrop (Galanthus nivalis) blooms any time from January through March. Sometimes they push through the snow or a carpet of brown leaves under trees.  Hardy to USDA Zone 4-7, they prefer cool weather, partial shade, and rich soil. They are not fazed by deer but may get relocated by squirrels. By late spring, the green, strap-like leaves die back and the bulb lies dormant during the summer.

Snowdrops seem so simple, so humble, like servants to queen daffodils and regal tulips. Here in America we give them a nod as a small sign that spring will come soon. In Great Britain, however, snowdrops enjoy a cult status. The English have been breeding snowdrops extensively since the Victorian area, yielding over a thousand cultivars. They quite literally put these small perennials on pedestals and table top arrangements during judging shows and grand events.

To me they all pretty but look similar. To a galanthophile each flower is distinct and beautiful. Galanthophiles collect the cultivars, some of which can be costly. They may also collect other Galanthus species — there are about 20 species that vary in bloom time and size.

Here in this country, we are not able to access a wide variety but a good source for many snowdrop cultivars is Carolyn’s Shade Gardens in Pennsylvania. Another source is to visit a private garden or sale such as David Culp’s annual Galanthus Gala which will be on March 3, 2018, in Downingtown, PA. David, a well-known breeder, lecturer, and author, has a collection of snowdrops, among other plants, in his gorgeous gardens at Brandywine Cottage. The Galanthus Gala is open to the public, registration is required, and includes speakers and other plant vendors.

Spring-Blooming Crocus: Small but Loud

crocus

crocus at Brookside Gardens

February brings the spring crocus. These ephemeral beauties are actually perennials. After blooming in February and March, they go dormant in the summer and reappear next spring. Crocus are grown from corms, which are relatively small and cheap compared to other spring blooming bulbs. The plants do best in full sun and well-drained soil. They are great for naturalizing in a lawn, planted in drifts, or in alpine or rock gardens, or in containers. You can force them to bloom indoors in low growing containers, much like a flower arrangement.

The most commonly planted are hybrids of the large flowered Dutch crocus (Crocus vernus), the golden or snow crocus (C. chrysanthus), and tommies (C. tommasinianus). These work well for large drifts outside. For more singular plantings, such as an alpine or rock garden or containers, look into the more unusual species.  There are many species and nurseries that specialize in bulbs such as Brent and Becky’s Bulbs and Old House Gardens should have them.

Purchase corms in the fall. All types of animals will either eat the corms or move them around so plant deeper than you would for other bulbs. I have read from 3 to 6 inches but it depends on the actual size of the corm. Plant many to ensure that a good number will survive and bloom. The tommies are the most squirrel-resistant because they contain alkaloids that the other crocus plants do not. Also, if you are trying to establish drifts in the lawn, it helps to cut the lawn as late as possible to ensure the crocus leaves can produce food for the next season.

crocus

crocus in my lawn

The former owner of my house planted these purple crocus plants more than 15 years ago. Every March, they bloom in the front lawn and I have never fertilized or divided them. The little blossoms don’t have much of a stem so I put them in tiny vases on my desk. The flowers last only a day or two but their declaration that spring is coming is loud and clear.

Tips for Starting Seeds in Your Garden: Planting in the Spring

lettuce in container

Recently, I posted an article called Tips for Starting Seeds for Your Garden. The post was about starting seeds and the importance of distinguishing between warm versus cool season plants or seed. It further explained how and when to sow seeds for warm season plants. This is the second part of the post: a focus on cool season plants.

Starting Seeds in Ground or Containers

In my zone 7 Northern Virginia garden, there are many vegetable and herbs that I can start growing outside in early spring. This means I don’t have to start them indoors under lights. Not only do these particular plants prefer cool temperatures, a light frost should not harm them. I tend to start most of my cool season plants by seed in containers on my deck. Container soil is warmer than ground soil. Also, it is easier to check on them by walking on a wooden deck than to have to trample through wet, soggy soil in cold weather. By summer, most of these types of plants have bolted (i.e., flowered and gone to seed so leaves are bitter). After pulling and discarding into the compost pile, I re-stock my containers with warm season annuals such as different types of basils and bush beans.

When to Sow Seeds in Early Spring

Using davesgarden.com and my zip code, I calculated my average last frost date to be April 30. March and April are still cool and there is a possibility of a frost or even snow. From the list of cool season plants or seeds I want to grow, I calculate which I can start at what number of weeks before April 30 and which would benefit from containers on the deck or directly into the soil. If a seed packet does not provide this information, try asking your local extension agent, online seed catalogs, or read a printed seed catalog or a gardening book. A few online seed catalogs that provide quality descriptions for this are Burpee, Johnny’s Selected Seeds, Botanical Interest, Southern Exposure Seed Exchange, and Renee’s Garden.

chervil

chervil is a spring herb

Sowing Often for Continuous Harvest

For some cool season crops, sowing every couple of weeks ensures a continuous harvest until summer. For example, our family likes to eat lettuce and spinach so if I start sowing in early spring and again every other week, I will be able to continue to pick leaves for a family of four up until summer. By summer, the weather will be too hot to germinate spinach and lettuce easily.

spinach seedlings

direct sow spinach seedlings in container

Check if the seed package recommends growing in soil or if they can be grown in a container. If you only need a little arugula, grow in a shallow container. If you only need one borage plant, grow in a larger container (it is a larger plant). Chervil is so ephemeral it is best to grow in a medium container so you can access and harvest as much as possible. For plants that tend to flower and drop seed, I find it helpful to have a patch set aside. I have parsley, cilantro, and calendula patches in the backyard so I sow the seeds directly in those patches. Of the plants below, peas are the only ones that need vertical structure. They should be planted next to a trellis and “trained” to wrap around it. I grow sugar snap peas in the ground next to a wire trellis but there are some variety of peas that can be grown in containers with stakes. Here are common cool season plants that can be grown by seed:

  • Alyssum
  • Arugula
  • Asian greens
  • Beets
  • Borage
  • Calendula
  • Carrots
  • Chervil
  • Chinese cabbage
  • Cilantro
  • Dill
  • Endive
  • Greens
  • Kale
  • Kohlrabi
  • Lettuce
  • Mache
  • Mustards
  • Nigella
  • Pak choi
  • Parsley
  • Peas
  • Radish
  • Spinach
  • Sweet peas
  • Turnips

My Cool Season Seed Plan

Just before March 15

Burpee and Botanical Interests Sugar Snap Peas: Soak overnight in water and then plant seed in small plastic pots with soil. When 2 inches tall, transplant outside in ground against trellis. No need for indoor lights.

March 15

April 1

  • American Meadows Scarlet Nantes carrot, sow in large deep container on deck and in ground
  • Renee’s Garden Slo-Bolt Cilantro, sow directly into cilantro patch in ground

April 15

  • Repeat lettuce, seed, radishes, and kale
  • Start borage in large decorative container
  • Start arugula in medium container
pak choi

direct sow pak choi seeds in ground

 

Time to Start Sowing Cool Season Flowers and Brassicas

mustard

This week on Facebook, Southern Exposure Seed Exchange, a Virginia-based seed company, reminded us to start cabbage, celery, celeriac, cauliflower, and bulb onions indoors (from seed, under lights). However, if you are worried about the dreaded cabbage worm and other pests, Margaret Roach in New York just interviewed Don Tipping from Siskiyou Seeds on her website, awaytogarden.com, for tips on growing brassicas and preventing the cabbage worm. Brassicas are members of the cabbage or mustard family (Brassicaceae) that include cauliflower, collards, broccoli, kohlrabi, kale, and the mustards, among others. Popular vegetables to grow here but they are susceptible to cabbage worm and flea beetle.

love in a mist seed pod

Claire Jones, Maryland garden/floral designer, tells us on her blog, The Garden Diaries, that now is the time to sow cool season flowers. She has sown seeds of calendula, love in a mist, poppies, and bells of Ireland outside, directly into the soil, when it was workable.

If you are new to the concept of cool season flowers, check out Lisa Ziegler’s website, The Gardener’s Workshop. She wrote the book (quite literally) because she has a cut flower farm in Newport News, Virginia. Her website has two virtual workshops (a series of short videos): one to learn how to start seeds indoors and one on growing cool season flowers. Last year, I was inspired and grew snapdragons, calendula, and love in a mist.

love in a mist flowers

snapdragons

New Cultivars of Wintergreen for Bright Red Berries

This week I attended the Mid-Atlantic Nursery Trade Show (MANTS), an annual horticulture trade show at the Baltimore Convention Center.  MANTS is one of the largest shows with over 10,000 attendees and almost a thousand companies exhibiting at booths in the Convention Center. The companies are wholesale, they are not selling directly to customers or the press like me. However, I enjoy attending because it provides me a glimpse of new products and plants and trends in the gardening world. This year, I discovered several new plants and gardening products which I will describe in future articles.

One plant in particular stood out for me.  I was struck by how many times I saw Gaultheria procumbens in containers either as a decoration or as a new cultivar. I have seen the species for sale in local nurseries before but they were always so small and scrawny I never bought them. The plants at MANTS were large with exceptionally large berries.

Briggs Nursery had a display of Berry Cascade and Cherry Berries. Cherry Berries has very large red berries, almost like cranberries, while Berry Cascade had berries appearing the entire length of the stem, forming a cascading effect. Because Briggs is a wholesale nursery, you would have to ask your garden center to order these if they don’t already have them in stock.

Cherry Berries

Berry Cascade

Monrovia, a plant company that sells directly to consumers via their website and through garden centers, had beautiful, healthy plants in their signature containers. Their website features two types: Very Berry and Red Baron. Red Baron has more and larger bright red berries.

Monrovia’s Gaultheria plants

I was lucky to find Peppermint Pearl at MANTS. Peppermint Pearl is unusual in that the berries first appear white in the fall and change to pink by early spring.

Peppermint Pearl, already turning from white to pink

Botanical Collections, a wholesaler of Kew pottery from London’s Royal Botanic Gardens, used the red berries of Gaultheria to show off their products.

Red berries add color to Botanical Collections’ pottery

And here is another photo of Gaultheria modeling this container.

Gaultheria procumbens, also known as teaberry or wintergreen, is a groundcover that prefers shade and moist, acidic soil (think “woodsy environment”). Hardy to zone 3, Gaultheria is an eastern North American native plant. It blooms small, white flowers in the summer followed by the berries in the fall. The berries can last until spring and are edible but it is the leaves that produce that aromatic wintergreen scent. Native Americans used the leaves to make a medicinal tea, hence teaberry, to alleviate pain (much like aspirin).  The name wintergreen comes from the fact that the plant is an evergreen. Its green leaves turn bronzy red or purple with the cold weather and remain above ground throughout the winter. Although the plant should be grown outdoors, its red berries make it a great holiday gift plant. Now that there are new cultivars with even larger berries, I will have to add Gaultheria to my Virginia garden as a native herb evergreen groundcover with winter interest!

‘Twas the Night Before Christmas for Gardeners

I read an old version of A Gardener’s Christmas in a Journal of the Garden Club of Virginia. The author is unknown so I took a few liberties to bring it up to date. Merry Christmas!

 

A Gardener’s Christmas

´Twas the night before Christmas,
And all through the yard
The branches were bare
And the ground frozen hard;

The roses were dormant
And mulched all around
To protect them from damage
If frost heaves the ground;

The perennials were nestled
All snug in their beds,
While visions of fertilizer
Danced in their heads;

The newly planted shrubs
Had been soaked by a hose
To settle their roots
For a long winter’s doze;

And out on the lawn
The new fallen snow
Protected the roots
Of the grasses below;

When, what to my wondering
Eyes should appear,
But a Prius full of gifts
Of gardening gear;

St. Nick was the driver
A jolly old elf,
And he winked as he said,
“I’m a gardener myself.

I’ve brought new seeds
And light systems, too,
Give them a try
And see how they do.

To eliminate weeding,
I brought bags of mulch
To attract the pollinators,
I have flowers for best results.

To add to your joy,
I’ve plenty of herbs
And ornamental grasses
For your hell strip curb.

For seed planting days,
I’ve a trowel and dibble.
And a roll of wire mesh,
If the rabbits should nibble.

I have the latest books
Plus some gadgets you’ll love;
Plant stakes and frames,
And waterproof gloves.

Here are sharp shears
And a new compost pit
And, for pH detecting,
A soil testing kit.

With these colorful flagstones,
Lay a new garden path.
For the view from your window,
A bird feeder and bath.

And last but not least,
Some well-rotted manure.
A green garden year-round,
These gifts will ensure.

Then, jolly St. Nick
Having emptied his load,
Started his Prius
And took on the road.

And I heard him exclaim
Through the motor’s quiet hum,
“Merry Christmas to all,
And to all a green thumb!”

Selecting the Perfect Christmas Tree and Poinsettia

If you are spending this weekend looking for the perfect Christmas tree, check out the article on Merrifield Garden Center‘s website, “Selecting the Perfect Christmas Tree,” by Michael Fahey.  For video format, watch David Yost when he explained how to choose the perfect tree on an archived Merrifield television show (old timers here may remember that Merrifield used to have a Saturday morning television show on gardening).  To select healthy poinsettia plants, watch Dr. David Clement, University of Maryland Extension specialist, describe what to look for and tips on taking care of this lovely euphorbia.