Perennials Archives

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.

A Little Information on Dianthus

Dianthus Cranberry Ice

Dianthus Cranberry Ice

On special this week in our perennial department is the entire selection of Dianthus. Garden dianthus are commonly called pinks, because the edges of the petals are often notched as if cut with a pinking shears. We also have some called “Sweet William,” which is usually grown as a biennial (they tend to die after a season of flowering, but will usually seed themselves and thus return to your garden year after year). Dianthus is one of the mainstays of the “English Cottage Garden” look, which points you in the direction of their siting and care.


In our area, the pinks give their best bloom in spring—April, May, early June. Sometimes they cough up a few flowers in the summer and fall as well, especially in cooler years. As perennials go, they tend to be short-lived. You may find that they need to be replaced after several years.
They offer pink, red, white or bi-colored flowers, often very fragrant. Carnations, the cut flower, are a type of dianthus, so that might give you a sense of the fragrance. (Carnations are not good garden plants, but if you use your imagination, some of the double pinks look like wee carnations.)

Dianthus 'Feuerhexe' or Fire Witch

Many of the cultivars offer silver or blue evergreen foliage, which can be attractive when the plant is not in bloom. We found over the years that an older variety, ‘Bath’s Pink,’ can make a good silver ground cover for small areas. Our most popular dianthus is ‘Feuerhexe’ or “Fire Witch,” bearing electric pink flowers on blue foliage. It was the Perennial Plant Association’s Perennial of the Year a few years back. This time of the year we generally have a dozen or more cultivars in stock, with the early ones like Fire Witch and ‘Tiny Rubies’ just coming into bloom now.

Even when not in bloom, 'Bath's Pink' can be a nice groundcover, photographed at the Missouri Botanical Garden in July.

Plant them in containers, or on a slope, or in a raised bed… somewhere with good drainage. Sodden winter soil will kill them. Add a little lime to the soil when you plant, and site them in a sunny spot. As with many perennials, if you have a chance to pluck off the dead flowers, it will encourage the plant to send up additional blooms, extending the flowering season. My experience is that they go more or less heat dormant in the hottest part of summer, sending out new growth starting early to mid-September. The new growth will have more intense blue/silver foliage. Don’t prune, trim, cut back, etc during July and August. Do it in the early fall.

Dianthus don’t mind the cold! Snow on pots of Dianthus, April 7, 2007, Behnke’s Garden Center at Beltsville

As I age, I am becoming more and more fond of fragrant flowers. (This is a change over time. I used to be a hardcore horticulturist, interested in flowers that look and smell like rotten meat and are pollinated by flies and carrion beetles. I’m still interested, but no longer want them in the garden. Much to the relief of the neighbors.) If I didn’t happen to own a wooded lot without much sun, you can bet that I’d save some space for the pinks. Perhaps at that retirement cottage we plants people all dream about…

Tyne Cot Military Cemetery, Belgium

Hellebores – The Glory of the Garden

This was written several years ago, so certain references like “lack of snow cover” may sound a little odd. Overall, the information is still good. [Editor]

The warm weather of the previous weekend perked up both the garden and the gardener, as I ventured outdoors to do some projects. The foliage on many of the “evergreen” perennials burned this year, due to the cold weather in January and February combined with lack of snow cover. I trimmed the Epimedium to the ground, in anticipation of its April flowers, and cut the old leave off of the hellebores.

Some years the hellebore foliage looks pretty good right into late spring, but this year, there was some edge burn. Easily taken care of by just cutting those old leaves off at the ground while being careful not to cut the new leaves and flowers emerging from the center of the clump.

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