Perennials Archives

The Sun, the Moon and the Stars

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.

Heuchera – Coral Bells

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!

Ferns – All the Colors of Green

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

Gardening Basics – A Little Bit on Herbs

One of the easiest and most rewarding things for a gardener to grow is a selection of herbs. It’s fun to use your own fresh herbs in cooking, they are interesting to learn, the most common ones all have the same growing requirements, and animal pests tend to leave them along.

First, cooking. That is when you make your own meal from a series of ingredients instead of buying in at McDonald’s or tossing a frozen bag of pasta into the microwave. Just thought you might want to know. It takes a combination of time and thyme, but on those days when the weatherman has you cowering inside from the elements (Rain today, run for your lives! Hot today, for goodness sake don’t go out there!!), it can be fun to spend some time following a classic Julia Child recipe instead of downloading apps onto your I-phone. But that’s just me.

Anyway: more on herbs as I understand them. Spices and edible herbs are used for flavoring food. Spices are tropical, are often seeds, and often come from trees, shrubs or vines (pepper; cinnamon which is tree bark; vanilla which is the seed pod of an orchid). Our common herbs are more temperate in origin, and look like your standard garden plant, sometimes annuals, usually perennials.

Just because something is called an herb DOES NOT MEAN IT IS EDIBLE. Herb usage was traditionally medicinal, the province of shamans, monks and witches; the flavoring aspect was just a byproduct. (Take two leaves and call me in the morning, if you’re still alive.) Example: Rue is one of the herbs that is usually sold at garden centers. It’s a pretty blue-leaved plant, but can cause a dermatitis reaction like poison ivy on some people (you will rue the day…). So, once you step away from the common herbs like basil and thyme, Google that bad boy before you throw it in the soup.

Right off, I can’t think of any that are North American in origin; they often come from the Mediterranean area, basil originally from India I think. On the whole, they do best in full sun and need good soil drainage. The flavoring frequently comes from oils that develop most strongly in hot weather. That’s why your basil tastes better in the summer than in the winter. When dried, some herbs hold the flavor, others lose it, especially the leafy herbs. That’s why dry basil and parsley are not as good as say, dried rosemary.

Harvest your herbs early in the day for best flavor. Growing them on a sunny windowsill? Some herbs are okay in a south window, but especially in winter, it’s going to be tough to have enough light for them to thrive or develop much flavor.
The strong flavors of herbs should repel deer, so if you have deer problems, try planting some sage or thyme. Let us know if they graze on your basil. We keep lists.

A good place to see herbs in action, so to speak, is at the huge herb garden at the National Arboretum in DC. Depending on what they have going on this year, will be able to observe things like which lavenders or rosemary varieties do better in our climate, and which herbs are more ornamental. The herb garden is near the visitor center and the Bonsai pavilion. The Arboretum is free, of course, and well worth a trip any time of the year.

For beginners, basil is a great plant, and can easily be grown in a pot on a sunny deck. It is an annual, it grows fast, and you harvest the leaves and soft tips. As the summer progresses and the plant matures, clip off the flower spikes and discard them. Make your own pesto. Probably okay to plant now. They are notorious for rotting off at the soil line in cool weather.
Also easy to grow: parsley (grow as an annual); dill (annual); fennel (seeds out badly, watch out for this one); chives (perennial); thyme (perennial); sage (perennial); oregano (perennial); and French Tarragon (perennial).

Rosemary and lavender: perennial but touchy; siting in good drainage is critical, and for rosemary, some varieties are more winter hardy than others. We have a huge rosemary shrub at the exit at our garden center in Beltsville. It is in a raised bed with great drainage, and has the heat of a poorly insulated building for company in winter. Here’s hoping you try some herbs this year!

Sedum surrounds stepping stones at a private garden in Saint Louis

There are some places that lawn grasses just don’t do well in.  If you’ve planted (and replanted, and maybe replanted again) grass into an area with little success, you might consider a perennial ground cover.  There are perennials for dry sunny areas, including thyme and sedum; dry shady areas (barrenwort), and plenty for just average sun and soils–maybe mazus.

Some premium groundcovers like the barrenwort are available only in larger pots; and of course we have the standard pachysandra and liriope for large scale plantings in the shade.  If you want to play around a little, we offer  two lines of perennial ground covers–Stepables and Treadwells–they offer lots of possibilities to end the spotty lawn blues; especially for small scale plantings.

My view on perennial ground covers is that they are going to be best in limited traffic areas—between flagstones, in rock walls, in containers, but not where the kids are playing football every weekend.  Try them in a limited area to start, and see how you like them. You can always expand the area later on if you are happy with the results. Heck, they’re ground covers–you may be able to dig out divots and expand the area from your own initial planting after the first season.  Remember that especially in the first season, they will need to be weeded and watered so that they establish and spread.

Mazus at the Missouri Botanical Garden, Saint Louis

Also consider that if they are really happy, many ground covers can be very aggressive and spread into lawns and flower beds.  Another reason to try a dozen in a limited area to see how they perform over the season before ripping up the entire lawn.  Ajuga and lysimachia, for example are notorious for moving into lawns and also are on lists of invasive species.

Ajuga and sedum between stepping stones at a private garden in Saint Louis

I have seen some terrific  plantings of Stepables and Treadwells, and when done well, they definitely are more interesting than turfgrass.  They are especially nice when setting off a bench, birdbath, statuary or some other garden fixture for example.  Remember that even shade-tolerant ground covers need light to live and grow thickly.  You are never going to get a lush ground cover under a spruce or pine tree that casts a year round, dense shadow.

Remember, too, that the ground covers can be used in your mixed container plantings.  Mixed containers need elements: a “Thriller”—the focal point, often with a vertical aspect;  a “Filler”, something for the mid-level; and a “Spiller,” to cascade over the edge of the pot.  Successful container plantings often resemble exuberant raised fountains, with the thriller being the jet of water; the filler the area where the water splashes to the container; and the spiller being the water cascading down the sides.

Shady groundcovers: woodland creeping phlox and Epimedium at the author's home

Many of the ground covers, like the above mentioned lysimachia (moneywort), English Ivy (a container is the only place it should be planted), wirevine (Muhlenbeckia), or mazus being types that you might try as “spillers.”

In addition to the Treadwells and Stepables, we have other ground covers available periodically, including barrenwort (Epimedium) and hayscented fern for example; plants  that for one reason or another (either cost or production issues)  keep them from being included in the above programs.

Behnke’s also has the standard ground covers, the usual boring liriope, pachysandra and vinca. So boring, we relegate them to the woody plants department instead of perennials.  We have a mystique to protect, after all.

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