Asclepias tuberosa, 'Butterfly Weed'

Most people are familiar with milkweed as the host plant for the Monarch butterfly. However, milkweed is so much more than just a butterfly plant. Milkweeds are one of our most stunning and attractive native wildflowers. Boasting fantastically bold colors such as luscious orange and creamy-lipstick pink, milkweeds are garden gems that no landscape should be without.

[Note from the Behnke Perennial Buyer: we try to have Asclepias tuberosa in stock in season, which is late April through August. Right now we have several dozen at Behnke’s at Beltsville, a handful at Potomac. Asclepias incarnata is most easy to obtain in April and May. Being tall, while it is nice in the ground, the latter tends to be unattractive in a pot in the summer. There are a few at Potomac.]

Asclepias tuberosa, 'Butterfly Weed'

Three milkweeds are indigenous to our area, but only two are widely available through retail nurseries. The most popular is butterfly weed, Asclepias tuberosa. Butterfly weed is an easy-care beauty for the sunny border. Laughing at drought, deer, and disease, this plant is as maintenance-free as it gets. With a color reminiscent of juicy oranges, butterfly weed is one of those seventy-mile-an-hour plants, meaning you can still see it from your car while driving down the highway at seventy miles an hour.

The show-stopping blooms on this plant aren’t the only attribute to this garden-winner. The butterfly weed in my garden has withstood temperatures hovering close to and above the one hundred degree mark, without even so much as a hint of rain, and it still looks as fresh and cool as a tall glass of orange juice.

Butterfly weed can grow from two to three feet tall and belongs in the front or middle of the border. Even though the blossoms are bold, butterfly weed blooms are not brash and look great paired with nearly any other color. For a show-stopping combination, try it with Liatris spicata, blazing star. The purple spikes of blazing star combined with the flat-topped orange flowers of butterfly weed are a stunning arrangement. Add some Panicum virgatum, switchgrass, for a soft background and some movement, and you have a native butterfly garden that will be the envy of the neighborhood.

Asclepias incarnata 'Swamp Milkweed'

On the other hand, as its name suggests, swamp milkweed, Asclepias incarnata, requires a bit more moisture to keep it happy. However, swamp milkweed is no less a winner. Its beautiful rosy pink flowers lend a touch of tenderness and charm to the perennial border. Growing taller than its cousin the butterfly weed, swamp milkweed can easily reach three feet tall. Pair it with some yellow Coreopsis verticillata ‘Moonbeam’ or Rudbeckia fulgida, otherwise known as black-eyed Susan. Add some Perovskia atriplicifolia, Russian sage, for the background; and you have just created an eye-catching vignette that will certainly catch the attention of all the butterflies in the neighborhood.

Milkweeds are most often known as the host plants for the dynamic orange and black monarch butterfly. The color of the butterfly, and its familiar white-yellow-and black-striped caterpillar, advertise its toxicity to predators and therefore keep it safe from marauding birds. Monarch butterflies can only survive on milkweed plants and follow the milkweed trail north in spring and back south in the fall during their extraordinary and implausible migration. So planting milkweeds in our landscapes will help the monarch butterflies to survive their impossibly long journey. However, monarchs are not the only insect that survives on milkweed. The elegant look-alike Queen butterfly is also dependent on milkweed as its larval host.

In addition, many curiously beautiful beetles enjoy milkweeds, such as the aptly named milkweed beetle, which resembles an oblong, whiskered ladybug with its red body and black polka dots. This beetle is a beauty to behold and, unfazed by close human contact, seems to stop and smile for my camera lens as I lean in close for a picture. But most of all, milkweeds offer the sweet, nutritious nectar that so many butterflies and other pollinators long for. Adding a few milkweed plants to your garden is almost like adding an entire butterfly garden in one plant. Butterflies, skippers, beetles, beeflies, and other pollinators dance from one flower to the next in utter delight, blissfully intoxicated by their drink of preference. It’s like a pollinator party!

In addition to feeding multiple insects by being a host plant and a nectar source, milkweeds produce soft downy fibers in late summer when their seeds mature. In nature, this down helps the seeds get carried off by gusts of wind so that new milkweed colonies can become established further away from the competition of the parent plants. These downy fibers are used by birds, particularly the American goldfinch, to line their nests and create soft cozy cups for their precious offspring. American goldfinches build their nests late in the summer when seeds become available as a food source, and when most other bird species have finished caring for their nestlings, so the silky milkweed fibers are available at the same time as the goldfinches are building their first nests of the season.

The fibers, although soft, are also strong, and historically have been used in textiles for making rope and twine. Sometimes the downy seed heads were used instead of feathers for stuffing beds and cushions. And since the downy fibers looked like soft, fine fur, they were also used in making hats. If you allow the seeds to mature and burst open in your own garden, you may be rewarded with some new plants the following spring. But be aware, milkweeds are slow to emerge in spring, and just when you thought your plants did not make it through the winter, they will finally awaken from their deep sleep. Mature milkweeds don’t like to be transplanted, since they have a long taproot, so transplant seedlings when they are still young to encourage success.

So if you are looking to add some new plants to your garden, why not try one of the milkweed species? Even if you already have some milkweed in your garden, studies show that butterflies find plants more easily that are grouped together, so it would be a good idea to add more milkweed plants to your landscape this year. The butterflies and goldfinches will thank you for it.

Natalie Brewer
Master Gardener

Coreopsis verticillata 'Moonbeam'

How would you like a plant that is drought tolerant, is heat tolerant, blooms for weeks, is deer resistant, is native, and is a butterfly magnet?  Does this sound too good to be true?  Well, if you haven’t tried Coreopsis verticillata yet, then it should be on your next plant-shopping list.  Coreopsis verticillata is known by many other names, such as thread leaf coreopsis, tickseed, whorled coreopsis, and pot of gold.  But I think it should be named ‘the sun, the moon and the stars’ plant, because it offers so much in exchange for so little.

Coreopsis verticillata is a perfect little plant.  Just plant it in a sunny location and it will gratefully respond by blooming with unabashed enthusiasm, beginning in early June and continuing for weeks.  When the first flush of bloom is over, shear it back lightly and you will be rewarded with more flowers in a couple of weeks. With attention, it will bloom on and off throughout the summer.  Its fern-like foliage is delicate, but don’t underestimate the vigor of this little plant by its dainty looks.  Coreopsis is not fussy about soil conditions and does not need much water once it is established.  When other plants are wilting and looking tired from the heat and humidity, coreopsis continues to look as fresh as a cool breeze.

Coreopsis verticillata 'Moonbeam'

The native species, Coreopsis verticillata, can become two to three feet tall and has glistening golden blooms.  However, there are also cultivated varieties, such as Coreopsis ‘Moonbeam’, which was named the Perennial Plant of the Year in 1992 by the Perennial Plant Association.  Its flowers are a soft yellow and blend well with both pastel and bright color combinations in the garden.  The color of the flowers reminds me of sweet, creamy, whipped butter. ‘Moonbeam’ plants maintain a height of about two feet.  Another tried-and-true cultivar is Coreopsis ‘Zagreb,’ which is shorter and grows to about one foot tall with bright yellow flowers that look like little golden stars.

Coreopsis verticillata 'Zagreb'

In the garden, coreopsis can be successfully combined with many other summer blooming perennials and annuals.  I particularly like the combination of the soft yellow Coreopsis ‘Moonbeam’ with bright pink garden phlox (Phlox paniculata).  Or Coreopsis ‘Zagreb’ with its golden flowers can look stunning when planted with a purple-flowering plant, such as Blazing Star (Liatris spicata).  I am also fond of any coreopsis planted en- masse in front of a green backdrop, such as in front of a group of arborvitae, Thuja occidentalis.  The dark green arborvitae make the coreopsis flowers really pop.  Since its foliage is so fine, I recommend planting coreopsis in swathes or in groups so that its beauty is visible from a distance.

Perhaps the best attribute of this tough little plant is its unfailing ability to attract pollinating insects.  Coreopsis is a butterfly magnet and would be a wonderful addition to your butterfly garden.  Hungry butterflies, skippers, and other pollinators eagerly fly from flower to flower drinking the sweet nectar.  Birds are fond of the seeds that form in the summer and can be seen in autumn pecking at the seeds on the ground under the plants.  In fact, the only wildlife that is not a fan of coreopsis may be white-tailed deer.  They prefer other plants and will most likely leave your coreopsis untouched.

So the next time you are looking for an easy addition to your garden, try thread leaf coreopsis, tickseed, whorled coreopsis, or pot of gold.  Or, as I like to call it, go for ‘the sun, the moon, and the stars’ plant, Coreopsis verticillata.

by Natalie Brewer, Master Gardener.  Photos by Larry Hurley.

Native Wild Heuchera on a Cliff

Heuchera, commonly called coral bells, is a group of North American-native plants, with several species native to Maryland.

In fact, if you go to the C&O Canal National Historical Park in Maryland to see the Great Falls of the Potomac, you can easily spot some Heuchera pubescens (I think) or downy alumroot, growing in the cracks of the cliff as you cross the bridge from the mainland to the island. Talk about “good drainage!”

There are several very active plant breeders working with heuchera, crossing the many species to create new hybrids. The hybrids feature colorful foliage, and sometimes also have nice flowers, depending on what was used in the breeding. If Grandma Heuchera had nice flowers, the offspring might, too. In fact, I’m old enough to remember when all the heuchera we sold had green leaves and attractive pink, red or white flowers. These have fallen out of favor with growers to some extent, but we try to have some of them available from time to time.

Fern Athyrium Ghost, with Caramel, Larry Hurleys Garden

Personally, I find that even those without showy flowers make an airy display when in flower, in a wispy sort of way. Often times, though, folks just pluck the flowers off as a distraction to the foliage, sort of like turning one eyebrow into two.

In the last couple of years, a lot of attention has been given toward developing heuchera hybrids that actually survive in the South. There is a heat-tolerant woodland species called Heuchera villosa (one of those found in Maryland) that imparts additional vigor to the hybrid mix.

Heuchera Georgia Peach

These hybrids have larger leaves, and are not as shiny as the others. ‘Caramel’, ‘Mocha’ and ‘Georgia Peach’ are some examples. Siting is important with heuchera. They are good in containers, as long as the container is sheltered in the winter, say up against the building out of strong winds. In-ground, they need decent drainage, especially in the winter. Better on a slope than in a low spot. Sun for a few hours in the morning is ideal.

Life expectancy: if sited well, perennials come back year after year, but there is a limit, and some perennials have a longer attractive life span than others. They are perennial, not immortal. Peonies frequently outlive their owners, and may be the only thing remaining as a reminder of where a farm house once stood. A heuchera only outlives its owner if the owner has had a serious spot of bad luck. More than three years for a heuchera is pretty good.

Midnight Rose and Caramel

I have some ‘Prince of Silver’ still looking nice in their sixth year; ‘Caramel’ and ‘Silver Scrolls’ doing well in year four; and ‘Mocha’ and ‘Georgia Peach’ doing great in year three. In fact, the ‘Mocha’ are spectacular, if I do say so myself. And let me tell you, I tend to garden in the manner that I believe to be the way many of you do. I dig the smallest hole possible and cram the plant into it. I feel that this helps in my recommendations for plants that are easy to grow. Plus, I am essentially lazy and I get a discount.

Terri, with Midnight Rose

This approach does not work well with heuchera. Not well at all. My heuchs that have survived and thrived are in:

• A large raised planter in the carport, in potting soil, and
• An actual prepared flower bed under a big oak tree that I have added compost and pine bark mulch to over the years to improve the soil

Deer resistance: heuchera often shows up on deer-resistant lists. I would say it’s not a preferred food source like pansies or hostas, but they definitely will hit them. At Sandy’s Plants display gardens near Richmond (Sandy’s is a wholesale grower which supplies many of our perennials) the deer eat just the heuchera flowers. In my garden, they will hit the foliage. I don’t have a lot of deer pressure, and I find that in my situation, repellants work. I like “Deer Solution,” because it smells like cinnamon instead of a junior high school gym locker. Makes you less unpopular with the neighbors.

Heuchera in Windowboxes, Brugge, Belgium

If you have tried heuchera in the past, and failed, give them another try. Start with containers (they are great color accents), and see what happens!

Ostrich Fern and Mayapple - Hurley Garden

by Larry Hurley
Greetings, spore fans. It is said that Ireland has a thousand shades of green. That has nothing to do with ferns, and having been to Ireland I have to say that it’s green all right, but the subtle nuances escaped me. I digress and it’s only the first paragraph. So: garden ferns: like Ireland, mostly green. Pretty subtle, with some notable exceptions. Below are the ones that I have found to be the most reliable.

The ferns that we routinely carry are for the most part shade plants, little forest-floor guys. Probably the most sun-tolerant is the Sensitive Fern (Onoclea sensibilis), called that because at the first appearance of frost in autumn, it dies to the ground. It’s native and a colonizer—when happy it spreads aggressively; you’ll find it in the sun along the side of the road in ditches, along stream banks and so on. We have it from time to time, this not being one of them.

Autumn Fern - Hurley Garden

I think the most shade-tolerant fern in my experience is the Autumn Fern, Dryopteris erythrosora. So called because the new leaves are sort of copper colored, like autumn leaves. They are evergreen, and at my place perform happily in miserable conditions between a wall, a shed, and the shade cast by a nearby American Holly tree. They are about 24 inches tall, and have been thriving in that dead zone for about 4 years now.

Got moist spots? Three of the natives do well in wet soils with protection from afternoon sun: Cinnamon Fern (Osmunda cinnamomea), Royal Fern (Osmunda regalis) and Ostrich Fern (Matteuccia something). They are happy in a rain garden or near a downspout or in that low corner of the yard, but also do okay in regular garden soil. The Ostrich is the most sensitive to drying out, and I find that by August they are looking pretty bad.

Royal Fern and Hosta - Hurley Garden

Cinnamon Fern is upright/arching, and the spores (fern “seeds”, dust-like and copper colored) are born on special fronds that look sort of like sticks of cinnamon. Ornamental, for a fern. The Royal fern has leaves that look more like an ash or locust tree; not very fern-like. The spores are borne at the top of the frond like a little crown. (Awww……) The Ostrich Fern has large ostrich-feather shaped fronds, and it has underground stems that allow it to colonize; aggressively in loose moist soil.

Another native colonizer, but about 18 inches tall instead of 3 feet like the Ostrich, is the light green Hayscented Fern (Dennstaedtia punctilobula). Hey, I’m doing these Latin names from memory: that one is easy to mess up so Pardon My Latin. It also spreads rapidly underground in loose soil, and in a formal garden, could be a nuisance. The crushed foliage smells like fresh hay.

If you have a drier location, the Christmas Fern (Polystichum acrostichoides) works well. Easy to spot in the winter on hillsides in the forests around here because it is evergreen, it is called Christmas Fern either because it is: a) green at Christmas, or b) because the individual fronds look vaguely like a Christmas stocking if someone points it out to you. I have had them growing for 25 years around the base of an enormous oak tree. They look a lot like the classic Boston Fern houseplant, a low arching clump, but dark green instead of light green. A non-native relative, the Tassel Fern, also does well here; more delicate with deep green leaves and copper colored ”hairs” on the stems for additional interest.

Japanese Painted Fern - Hurley Garden

For colorful foliage it’s hard to beat Japanese Painted Fern and its various hybrids and cultivars. Athyrium niponicum ‘Pictum’ and Athyrium ‘Ghost’,  two that we regularly carry. When the foliage emerges in the spring it is silver, often with burgundy highlights.

‘Ghost’ is light silver without the burgundy. Differences in the selections have to do with the intensity of the silvers and burgundies, and how long into the summer heat the colors hold. I have some that I planted 25 years ago that are wimpy little clumps; the newer selections can be breathtaking and are much stronger growers. Average garden soil for these.

The Japanese Painted is related to a native species, Athyrium filix-femina, or Lady Fern which is a good reliable upright fern for average soil. There is a hybrid called ‘Lady in Red’ which has red stems, same look, a little more colorful. Pretty subtle. Maidenhair Fern, Adiantum. I love ‘em. They are so delicate with their wiry stems and crape-paper thin foliage. Can’t grow them. I don’t think I provide the right conditions—they need cool, moist, good soil. And I find that slugs just adore them; I always find them covered with slug slime. So I have pretty much given up on them, but I bet you will do better.

And on and on.

As with any plant, meeting the conditions they grow in in the wild will improve your chances of success at home. If you want great Ostrich Ferns, plant them in a moist spot; if you don’t water very often (after the plant is established) then Christmas Fern is best. If you think slugs and snails are misunderstood and deserve a place in the garden, then by all means plant Maidenhair Fern. Ferns are generally considered to be deer resistant. I have had some trouble with rabbits in the last couple of years on both Japanese Painted Fern and Christmas Fern.

Ghost Fern and Maidenhair Fern - Private Garden in Saint Lewis

We carry a good selection of ferns through spring and into summer. The selection is a little different at the two Behnke garden centers, as we get shipments from different places at different times. The Potomac store at this writing is particularly packed with ferns and other shade plants. Right now (May 3, 2010), Potomac has more Ostrich and Maidenhair fern than Beltsville, for example.

If you are looking for a specific fern and want to know if we have it in stock, you can email me, Larry Hurley, at Lhurley@behnkes.net

By Larry Hurley: Perennial Plants Buyer

For the urban/suburban gardener, dealing with deer and other warm-blooded garden grazers is generally a case of discouraging their feeding in your garden. You can probably visualize herds of discouraged deer, walking dejectedly down the street, looking for some hosta to terrorize, their little white tails limp. Bad posture and everything. Sooner or later they will feed, it’s just that you are trying to get them to feed elsewhere, maybe on the next street.

One of the weapons in your non-ballistic arsenal is the use of deer-resistant plants. These are plants that have proven to be low on the deer’s feeding preference list. It doesn’t mean they won’t eat them, or try them and spit them out, just that on average, they are more likely to leave them alone when given other choices. For example, for me, Brussels Sprouts are Larry-resistant plants. And I don’t need any emails telling me I’m just not preparing them right, thank-you-very-much.

For deer, the resistant plants tend to fall into several categories—smell strongly (herbs); a lot of hairs on the leaves (often looking silvery); or taste bad/are poisonous. Note on the poisonous ones, that they are likely to be poisonous to people as well.

Most spring flowering bulbs are deer resistant: crocus and tulips are not. But daffodils (narcissus); hyacinths; fritillaria; scilla; muscari; galanthus and ornamental allium are, among others. Just don’t eat them. The alliums are various types of onions so they are strongly flavored; the fritillaria have a skunky odor when handled; daffodils are poisonous, and so on.

Some Other Fiends of the Garden:
If you have problems with squirrels digging up your bulbs, either to eat or just to play with, try placing a wide-mesh chicken wire on the soil surface. The bulbs will grow up through the mesh, and the squirrels can’t dig through it. Once the leaves start to grow through the mesh, you can remove it.

If you have voles (like short-tailed mice) that burrow around and eat some your bulbs during the winter, add sharp gravel or Vole Block (which is sharp gravel) to the soil around the bulbs when you plant them. The idea is that the sharp gravel is hard for the voles to dig through without poking their little noses (squeak!!), and they will go elsewhere where the digging is easier.

So, if the beauty of spring bulbs weren’t enough to get you to plant some this fall, maybe the idea that they can solve some of your “what can I plant that the deer will leave alone?” problems will entice you in to view our selection of fall-planted, spring-flowering bulbs.