Saturday, March 1, 2008

Long-Lived Perennials

By Kirk Jones
Community Gardener, Spring 2001

When I first started growing perennials, I thought of them as a sort of garden aristocrat, somehow more solid, important and serious than regular old zinnias and petunias. I was not very knowledgeable at the time and foolishly thought that a perennial, by definition, reappeared season after season, essentially forever. It didn’t take long for me to realize how mistaken I was. The dictionary has several definitions for perennial, and I can see now that in those early days I only knew about the first: “Lasting through the year or many years”, or maybe the second “Lasting an indefinitely long time.” Unfortunately, it is the third, botanical definition that contains the sad reality – “Having a life span of more than two years.”

Perhaps because of my earlier romantic notions about perennials, I am always a little angry and offended when a perennial dies after just a couple years. I mean, they’re supposed to be perennial, right? In my garden, the worst offenders are delphiniums, columbines, and baby’s breath. I have had considerable success with all three, but generally the second season is best. They may stick it out for a third summer, but a fourth year is almost unheard of. If one does survive that long it is often in such a weakened state that I usually just put it out of its misery and start over with a new plant.

It is a further garden irony that many true annuals like poppies, cosmos, and larkspur are such reliable self-sowers that they are essentially perennial. I have had larkspurs and several kinds of poppies and cosmos reappearing at my Country Farm garden now for nearly ten years. If anything, they reappear altogether too reliably, usually in between strawberry plants or irises or any kind of little delicate thing I’m trying to grow. However, as indestructible as they are, I guess I agree with Sarah when she says that field poppies, with their flashy beauty and proflific ways are “the floozies of the garden.” Somehow, annuals like these are just a little cheap, a little common.

Given my frustration with perennials that die out after a couple of years and my mild disdain for annuals that are all too willing to reappear (everywhere) year after year, it’s no surprise that I’m especially attracted to long-lived perennials. These are plants that really do behave like those ideal perennials I imagined when I first started gardening. The clump up steadily, don’t require division, and reappear faithfully year after year after year, no matter how cold the winter or how hot the summer. There are actually quite a number of these long-lived, no fuss perennials, but there are only two I know of, peonies and gas plants, that can settle in and be left undisturbed for decades.

The most well-known, long-lived perennial is the peony ( Paeonae spp). Peony flowers can be single, semi-double or double and come in white, pink, red, and all shades in between. An individual plant will only be in bloom around one week, but by planting early, midseason and late varieties, peony season can begin in May and last for several weeks. Even without the flowers, though, peony foliage remains attractive throughout the season, from the time the burgundy red shoots first appear in spring until the leaves finally yellow in autumn.

I must say at the outset that I am no expert on peonies, but I’ve grown them long enough to have developed some opinions. In particular, I favor older varieties. One advantage of older varieties is price. There are hundreds of peony varieties available, and like most plants, the newer hybrids cost more. However, unlike daylilies and irises, where new varities often possess a wider range of color, higher bud count, or longer bloom season, most peonies are still white, pink, or red and remain in bloom for about a week. To my not very discerning eye, there is little difference between fifty or even hundred year old varieties available from Gilbert Wild & Sons for $7-10, and newer cultivars available from specialty growers like Klehm for five or ten times that price. In addition to price, though, to me there is something romantic about growing varieties that could have been planted by my grandparents or great grandparents. I especially like to imagine that if my grand parents did plant a couple peonies, back before the first World War when they got married, those same plants might still be there. Properly planted and carefully sited, a peony can easily outlive the person who plants it.

Planting Peonies
Peonies are best planted in the fall. If you mail order the plants (see sources), they will arrive as dormant roots in October. Peonies prefer full sun and resent root competition from trees and bushes. As I learned the hard way, they also don’t like being moved, so choose the site carefully. Peonies get large so you need to allow about a three foot diameter per plant. Again, the plant is going to be there a long time, so prepare a big hole, a couple feet across and eighteen inches deep, and enrich it with added compost, well-aged manure, and bone meal. Correct planting depth is critical. The dormant peony root will have little pink nodules or eyes that are the buds for next year’s shoots. These need to be covered with 1 ½ to 2 inches of soil, no more. This should be measured, not estimated, because peonies planted too deep with not bloom.

Peony Care
While the planting instructions my seem kind of fussy, once established, peonies will return year after year with essentially no help at all other than keeping the weeds at bay. If you want to grow the double varieties, peonies do require staking or the flowers will be head first in the mud after the first rain storm. There are special wire hoops made for peonies, or you can just hammer a few sturdy stakes in around the plant and hold it up with twine. The peony foliage will grow through the twine and mostly disguise the stakes. In the fall, the dead stems should be cut down slightly below ground level, taking care not to disturb the eyes.

Moving Peonies – A Cautionary Tale
I had read that peonies resent being moved, but I had hear this about other plants, moved them anyway and gotten away with it. So, when I decided that my five-year-old clump of “Sarah Bernhardt” was in the wrong place, I figured if I took a really big dirt ball, and did it really early in the spring before the plant had even sprouted, old Sarah would never know any better. When the peony sprouted on schedule in the spring and bloomed normally, I preened a bit and thought, “all those garden writers just don’t know how to do it.” However, the following year, the peony didn’t bloom and only grew to half size, and it did the same thing the next year, and the year after htat. I’ve now sold the house so I don’t know if it will recover this year – or ever. So, take it from me, this is one case where those garden writers who say that peonies moved improperly may, “sulk for years,” are telling the truth. The right way to move peonies is to lift the clump in the fall after the foliage has died back. Shake the soil from the clump and then divide the plant into divisions with between 3-5 eyes. Each division then should be planted separately as a new plant.

Gas Plant
Gas plant (Dictamnus) is not nearly as well-known or varied in form and color as the peony. They produce pink or white spikes of flowers in early June. Gas plants have thick, leathery leaves that smell like citrus when rubbed. Dictamnus gets the name gas plant because the flowers exude a volotile oil which will ignite if a match is held near the bloom. I can’t imagine how anyone initially discovered this, and it has never worked for me, but reliable garden writers say it is true, so I will probably keep trying. Gas plants clump up very slowly, and like a peony, are said to survive decades. They have big, fleshy tap roots and, like peonies, are also said to resent being moved. I did successfully move a gas plant, which is part of what made me think I could move that Sarah Bernhardt peony, but don’t blame me if you try it and it doesn’t work.

Dictamnus plants are kind of hard to find. If you are lucky and patient with starting seeds, you can try it, but books say it can take up to a year for the seed to germinate. I know I would never manage to look after a pot holding ungerminated seed for a year, so I’ve never even attempted it. After hunting around for several years, I finally found a tiny and expensive 3-inch plant with about 5 leaves at the Matthaei sale about 7 years ago. The next year it had 7 leaves and was 5 inches tall, and the year after that it maybe had fifteen leaves. At that point I decided it must be in too much shade and moved it to a sunnier spot. Two summers later it finally flowered. Dictamnus are not always so hard to get going however. A couple of years ago Flower Scent Gardens was offering gas plants, and I ordered another one which bloomed the year after I got it.

Start this Year
Ed Resmussen, the owner of The Fragrant Path, has a great line in his catalogue – “One cultural detail is certain – if not planted, they will not grow.” Rasmussen is referring to starting trees and shrubs from seed, but the same can be said for peonies and gas plants. It is sometimes hard to think that it may take a few years to grow a peony or gas plant to maturity when annuals and other perennials offer more immediate gratification. But, try to set aside a spot or two for these slow-starting but long-lived perennials. Like an old friend, they will stay with you forever, and you only come to value them more with each passing year.

Plant Sources
I have always bought peonies by mail order. You can also get them in pots at nurseries and the Farmer’s Market, but after my experience moving a mature plant, I will always want to start with a 3 to 5 eye root planted in the fall. Gilbert Wild & Sons (1-888-553-3715) or Reath’s (906-563-9777).

A couple years ago, Glenn Varner at Flower Scent Gardens (330) 658-5946 was selling gas plants. After moving I don’t have the catalog this year, but send for it anyway, it’s a great catalog. This year I also see that June’s catalog is selling gas plants.


Carol Van Rooy said...

Is a gas plant and a regular burning bush the same thing. I've scored a source for a gas plant, however after various online searches... it mentions a burning bush as being the same thing.

I routinely see burning bushes at nurseries and find it hard to fathom they are the same thing.

a2projectgrow said...

Hi Carol,

Thanks for your question. It is indeed the same plant. Dictamnus albus is the scientific name, and it is also sometimes called False Dittany or White Dittany