Plants: Perennials


Overlooked and Beloved:

I am so sick of the botanical powers-that-be constantly renaming these plants- that I refuse to even look up the latest changes. So you may have to google/correct any of my naming errors yourselves!

Japanese knotweeds are an invaluable genus for us here in the ‘retum.We just love them. Of course, part of the reason is that they love us! They are what I term “Hunka” plants and they hold their own quite well in the competitive root zones of our tightly packed beds and borders. Here are our favs to date:

Polygonum bistorta superbum – You will see here many swaths of this lovely sturdy 15″pink poker . It blooms for two full months in May and June,blooms a bit in fall, and is not attacked by pests or disease. It makes a lovely companion to iris , peonies, lysimachia punctata, geraniums, digitalis, campanula et al. Because the stems are rigid, it brings a welcome neatening affect to the garden picture , both as an edging plant and mid-border. Just as valuable, its leaves form a solid weed barrier. Its roots spreads lustily, particularly in moisture, but it is easy to remove.

Polygonum amplexicaulis Taurus and Firetail – these are not quite straight and orderly like the Bistorta, but their wiry 24″ tall stems topped with 4-6″ dark pink/red pokers- make for great weavers in the late summer and autumn borders.

Polygonum affine – the only one of the list to have died out a number of times here. Short 6″ stems on mats of small leaves; it makes a great edging plant.I prefer the red one, “Darjeeling Red” but it is very hard to find, and right now, we do not grow this. Sigh.

Persicaria polymorpha – This “astilbe on steroids” is comprised of 1-1 1/2″ thick hollow 6′H stems with palm sized green leaves. In mid summer it begins to bud and by July/August it is covered with tall stately wide white plumes.It is lovely in company with tall ornamental grasses, filipendula venustra rubrum, falopia variegata and other tall back-of -the- border perennials.

Persicaria Lance Corporal – I know of no perennial tougher than this one. It thrives in the junkiest soil, in full hot sun or deep dry shade, and it seeds itself everywhere (also very easy to remove.)Its bold maroon V marked leaves pop up early in Spring and by September, it is 20″ H and covered with wiry 6 ” long raspberry floral wands that last into November, making it a great companion plant for Corydalis Lutea, Geranium Rozanne, mums etc. In our quest to “cover every available inch”, Lance Corporal is our go-to plant for spots where nothing else will grow.

Persicaria Red Dragon – this is a wiry 4′ H exciting new introduction with medium size arrow shaped leaves variegated in a striped pattern of burgundy with light and dark moss green.

Persicaria Golden Arrow -10″H plants of bright yellow arrow shaped leaves. Makes for a handsome skirt around blue conifers and grasses.

Falopia variegata – Contrary to popular belief, this 5-6′H ‘bamboo looking’ plant with large heart shaped green, white and pink variegated leaves, is not invasive. It spreads slowly, even in very moist soil. Its Spring emerging shoots are an amazing apricot color. It is particularly striking grown as an understory shrub (it is very convincing as such) which Broken Arrow is doing so successfully in Ct.

Falopia Crimson Beauty – Large heart shaped green leaves give no indication of the coming glory, as the 4′H autumn plant is completely covered with large muted- rose/raspberry seedheads.


geranium rozanne and corydalis lutea, June


Movers and Shakers:
The Well Rooted Thug
The Inseedious Thug

Whatever the reason, PH, drainage, neediness, karma, most of us have plants that like us and plants that do not. Here at the ‘retum, we cannot grow echinacea(What!!??) for the life of us. After way too much money, we no longer try to grow it. The two plants that we do have- seeded themselves- and we let them be. An old-time green-gifted N.H. gardener, Robert Young, once told us it was “all in the PH”, meaning that every plant had its preferred ph and , if you could give it that, you could grow it. I believe him but just have never got around to doing extensive soil tests. Obsessed in some ways, but not in others……… Fortunately there are plants that do like us and this is my topic here.

One of the garden writings that most impressed me as a beginning gardener was Fred McGourty’s chapter on Garden Thugs in his funny and very useful book, The Perennial Garden. In that chapter he talked about letting the monarda and lysimachia duke it out for dominance in a particular border. My “Aha!” moment this morning is a realization that garden thugs fall into two camps. Oddly enough, they are quite literally, “the Movers” and “the Shakers”, i.e. Thugs that conquer with roots v.s. Thugs that conquer with seeds.

At the ‘retum, the rooted devils are by far the more scary. For us, aegopodium(bishop’s weed) is the worst weed of all time because its roots conquer the world. They are delicate, whisper-thin, and brittle. They readily make their way into the teeny tiniest spaces, such as siberian iris crowns, and then when you attempt to remove them, their delicate stems break readily. Where they break, unless you can remove the whole plant with its taproot, they sprout life anew. So, without Round-up or some-such, you cannot get rid of this evil thing. And get rid of it is what you have to do, unless you want to use it to fill, solo, a cement edged planting spot. For me, the ultimate irony is that golden and purple barberry varieties are lumped into the Invasives list in Ma.(along with their justifiably verbotten cousin, generic barberry) while nurseries in Ma. and across the U.S. are allowed to sell aegopodium.

So, who are the Movers and the Shakers? At the ‘retum, the Movers are (or, I should say, WERE) variegated aegopodium, lysimachia clethroides (gooseneck loosestrife), phalaris (ribbon grass), tradescantia, and sweet woodruff. Variegated bamboo and blue lyme grass we grow/control in sunken pots. (So much for the Movers!)

The Shakers are a different story. With these self seeding ‘darlings’( they are so easily removed with a gentle or firm tug)we rejoice in their migrations. But then again, we are of the ‘plant every square inch’ gardening camp. At the top of our most valuable Shakers list are corydalis lutea and persicaria lance corporal. Celandine major and eupatorium chocolate are close behind. All four will grow and colonize readily in shade(native dicentra will do the same but its faded colors don’t appeal to me.)Where nothing else will grow, these plants will settle in with flower and foliage appeal from April through to the season’s end in November. Other valuable shakers are purple perilla and cryptotaenia, both Japanese herbs with the invaluable attribute of having deep saturated purple stems and foliage. While perilla (‘shiso’ in Japanese cuisine) is technically an annual here, it is perennial through its self seeding. While perilla appears late in the garden, cryptotaenia’s trefoil leaves appear very early. Through mid June it maintains a short presence, good as an edging plant, but come July, it’s maximum 16-22″ height is reached . If allowed to, it puts out hardly perceptible sprays of teeny tiny pink flowers in July, and then loses its deep purple coloring, and goes to seed. At this point, we whack it down(unless we have already caught it and trimmed off the flower heads to prevent it seeding.) This is usually concurrent with our whacking of celandine major (and sometimes dicentra)whose 2-3 month period of prolific large buttercup blooms have been followed by less colorful but equally amazing 3″ pendulous fuzzy white seed pods, which have burst open, after which the plant yellows and dies back to the ground. Fortunately, the other Shakers, corydalis lutea, persicaria Lance Corporal, perilla and Eupatorium Chocolate, all wait til autumn to throw their seed, even though the corydalis and persicaria were among the first plants to appear in Spring. Valuable, eh?!! Valuable but prolific seeding plants that we do not want everywhere- carex grayii, and chasmanthium latifolium (oatgrass)- we grow in single clumps, and we religiously pick out nearby errant seedlings.

Carex Grayi- Beloved/Berated

I fell in love w/ Carex Grayi years ago when I saw it’s small bright green medieval mace-like(hey, what’s not to like?!!!) gumballs in the everything-grows-there PNW. We really enjoyed it when we added it to our chasm area but we soon realized that it seeded itself more prolifically than any plant we had ever encountered here(still true). It is in the very prolific sedge family.The short wide bright green grass blade/seedlings are extremely easy to remove, so we DID succeed in countering its randiness after diligently removing its many hundred offspring.We moved it to a spot abutting the driveway and it has not been a problem since then.

The Plants That Ate Chicago

We have a category of plants here that (hats off to Bill Cosby and his “Chicken Heart” routine) we call “The Plants That Ate Chicago.”

These “very aggressive” perennials are our least fussy, tough as nails, boundary leaping residents. We divide them aggressively and they come back twice as strong.

If you were looking for the plants that would most quickly cover a large area, you’d need look no further than:

Artemesia Oriental Limelight
Canadian Anemone
Carex grayi
Celandine major
Chasmanthium latifolium
Corydalis lutea
Eupatorium Chocolate
Heliopsis Lemon Queen
Lysimachia ciliata atropurpurea
Persicaria Lance Corporal
Polygonum bistorta Superbum
Rudbeckia Herbstsonne and Black Eyed Susan
Veronica repens Georgia Blue
Variegated Bamboo
Water iris

Return to Top