Aster (ASS-ter)
Common Name: same
For too
many years I headed into the fall season relying solely on mums
to provide the major blocks of color to my garden. No longer.
Asters (and I'm going to dispense with the italics, let's just pretend I've switched from the Latin to the common name) are an indispensable ally in the northern gardener's quest for sassy September and October bloom. You'll sometimes hear them referred to as "fall asters," since all but a few varieties save their stuff for football season.
Sure, they have some fungus problems — I have some very tall, old dogs that make it every year to astounding bloom, but usually enter the game in the fourth quarter with seventy percent of their leaves turned brown and crackly, whether I've kept at them with a fungicide application during the summer or not. But they're at the back of the bed, hanging out with the Boltonia, so all you see is their riveting violet purple color being projected from medium-sized, daisy-like flowers.
All asters are derived from the dozens of native species that abound in many parts of the globe, so even the fancy, high-priced nursery cultivars evoke a certain native noblesse.
The tall ones I mentioned are the New England Aster (A. novae-angliae) which top four feet in one of my front beds, so staking is necessary. But staking a mature tall aster might mean dealing with 20 or more stems, so I circle my tall asters with wire hoops held about halfway up.
I also grow the very popular A. x frikartii 'Monch' which grows to thirty inches and flails out rich lavender blooms, which look lovely dancing above and between the Solidago I plant in front of it.
The shortest variety I grow is the 12-inch tall 'Professor Anton Kippenberg,' a terrific little guy with rich lavender blooms.
There are many, many, many other sub-groups and varieties within the groups. But since nearly all of them are hardy to -40 degrees, it's worth the time to get to know the genus and sort out what you like.
Care and Use
With a wide range of heights, asters can fill in anywhere in
the herbaceous garden. While they are a sun-lover, they do fine
in my less-than-full-sun garden, but will disappoint in true
"part shade." They like soil with good organic content
kept evenly moist, and prefer that their roots be kept cool.
In clay or non-draining soils, they can rot out on you fairly
quickly, but in well-draining soils can easily last five to 15
years.
Asters benefit from division about every three years. Divide in the spring by digging up the plant and either ripping the clump apart or cutting it apart with a long serrated knife. Asters are not huge feeders. I give 'em a little 10-10-10 in the spring and try to remember to give them a second shot in mid-August, as buds are starting to form.
Asters flower in a variety of purples, blues, pinks, reds, and white, and look great with other fall-bloomers such as Sedum, Boltonia, Solidago, Cimicifuga, and grasses. They are a wonderful cut flower, and are also handsome when dried.
Solidago
Common Name: Goldenrod
Nice plant to talk
about this week, since the dozens of native species are currently
blooming along roadsides, in ravines, meadows, schoolyards, alleys,
farm fields, landfills, parks, forests, cliffs, and abandoned
lots all across Zones 2 through 4. It's not fussy, just pretty.
It's also one of the first perennials I bought when I started gardening, and I still have it, S. 'Golden Boy' blooming right now in a small bed at the entrance to my drive.
Native cultivars number almost 30. The one pictured, shot at my cabin, is either S. canadensis or S. ohioensis, both of which grow freely throughout north-central U.S. and across much of Canada. Could even be a natural hybrid of the two, it's nearly impossible to tell.
Cultivated varieties will give your fall garden a very commanding blast of gold to gold-yellow color that I can't imagine lacking. Some good varieties to choose from include 'Cloth of Gold' (dwarf), 'Golden Boy' (about 2'), 'Goldenmosa' (upwards to 3'), and S. rugosa, a big, mean dude that can get up to 4'-5'.
Care and Use
As you can tell by the plant's profusion in the wild, Solidago doesn't worry too much about soil or sun. While the plant performs well in full sun, mine bloom just fine with less than four hours of direct sunlight. The nursery varieties do need more water than those in the wild, around an inch per week, the same as, say, mums.
Plant at the front of the border (except for the tallest varieties) so that the various gold spikes and spears can drape over and be seen in all their glory. Combines well with everything we grow for fall bloom, especially sedums, asters, grasses, and boltonias. Hardy pretty much to Zone 4, those of you comrades a little farther north, give it a shot, but provide winter protection once the ground has frozen.
Bottomus umellatus
Common Name: Flowering Rush
At the shallow end
of a deep bay on the Winnipeg River in Ontario, I came upon a
sparse settlement of this astonishingly beautiful marsh flower.
Funny, I hadn't noticed it in previous years. Then I found out
why.
For my education concerning this extremely worrisome, invasive alien, I must credit my friend and budding young horticulturist, Ali Chalke, of Vancouver, B.C. She took one look at it and not only told me it was a troublesome weed, she had in her possession the Most Wanted poster.
Flowering Rush arrived in Canada with the earliest settlers, packed along with the animal feed and planting seeds, and since its introduction has steadfastly spread itself from Nova Scotia to Ontario, Manitoba, Alberta, Saskatchewan and British Columbia, essentially the length of Canada ("a half-hour later in Newfoundland"). It has also been confirmed in Minnesota and North Dakota.
The problem is, it doesn't belong in any of these places and is preparing to wreak hell. A quick study, Flowering Rush obstructs shorelines, clogs irrigation canals and other riparian areas. Its effect on native plants is as yet unknown.
Heading up the international study of this alien's spread and impact is Chris Eckert, Department of Biology, Queen's University, Kingston, Ontario. IF YOU SEE THIS PLANT, contact Eckert at eckertc@biology.queensu.ca at your earliest convenience, noting exact location and volume of the plant.
Flowering Rush is quite distinctive; rose-colored flowers, each one inch-wide, in umbrels, the plant growing in a leafless stalk one to four feet high, in standing water. Slender, grass-like leaves also rise from the water and will be in evidence—for the photo on this page I pushed one flower head off to the side for a clearer shot.
Looks like they need our help on this one. Pity. Gorgeous plant.
Aconitum (ack-oh NYE-tum)
Common Name: Monkshood
Here's a plant to dispel the feelings of despair and insecurity that sometimes befall northern gardeners—you know, on those days when you flip through the glossy pages of a national magazine and wish you lived, oh, 700 miles farther south.
Enough of those thoughts. Aconitum is exotic, bizarre, worldly, glorious, alluring, and hardy as hell. Plus mine blooms in mid-August, when most of the gardens on your block are fairly void of perennial color, having just finished phloxing themselves to death.
Monkshood performs best in part shade. The variety I chiefly grow, A. henryi 'Sparks Variety' exceeds four feet in height, and while this precipitates staking, its dark blue flowers are so magnificent and unusual it is well worth the bother. I have also attempted the highly touted, lone yellow variety, A. lamarckii, which grows to around thirty inches, but found it an utter disappointment in bloom. The flowers were small, few, and I don't call the color of a Caucasian baby's bottom yellow.
There are over a dozen varieties, all of which do best in light shade and fall primarily into the blue spectrum, with the exception of the aforementioned toddler. There are also a couple of pinks, A. napellus 'Carneum' and A. n 'Rubellum,' the latter being well worth seeking out.
For a low-maintenance, dependable performer that will not require staking, try A. X cammarum 'Bressingham Spire,' sporting robust stalks full of violet-blue flowers.
The common name comes from the flower shape, which resemble monks caps from medieval days, though some of the varieties have flowers more remindful (in shape) of the tall fuzzy caps worn by Buckingham Palace Guards.
Care and Use
Light shade as stated above, more sun than that only if the soil is not allowed to dry out. Likes soil kept evenly moist. I've never had any great pest or disease problems, but those are as inevitable as taxes if you let the ground go dry. Needs acidic soil, pH between 5.5 and 6.5, so some soil sulfur may be in order, in addition to copious amounts of peat and compost.
Use in the middle to back of the border, and give these beasts some room—two feet, at least, all the way around. I find the foliage attractive all season. I have a large clump that rises behind multi-colored coleuses, and looks magnificent before and during bloom. Hardy to Zone 3, you'll even have decent success to Zone 2 with proper winter protection.
Platycodon grandiflorus (plah-tee-KO-dun
gran-duh-FLOR-us)
Common Name: Balloon Flower
Figure this one
was due since it's currently knocking my and everyone else's
socks off in my main garden bed right now. I see a few more people
growing it every year, but still, it's not one of those perennials
I would call widely popular. It should be.
First, it's a mid- to late-season bloomer. A ton of flowers like to burn up the joint in June and July, sure, but what exactly do we have capable of headlining the show the first two weeks of August? Not enough, at least in my garden. Depending on variety, Balloon Flower blooms from the second half of July through most of August, probably the most notoriously un-colorful stretch of the northern season, from a perennial standpoint.
The common Balloon Flower blooms a stunning, classy, regal violet blue, star-shaped flowers held high (36") and assured above thin, finely-leaved stems. It's a very aristocratic-looking plant. There is a white, 'Albus,' and a pink, the very pretty 'Fuji Pink,' which comes up a bit shorter. There are numerous other varieties as well, some featuring double blooms, because you know the nursery industry couldn't keep their hands off something so perfect.
Care and Use: Balloon Flower is very easy to grow, preferring a slightly acidic soil with decent drainage. This is one of those plants many books list as full-sun that does beautifully in my part-sun front bed (four hours of direct sunlight, high shade rest of the day). They like to be kept moist, but I don't water Balloon Flower any more than I do, say, tall phlox, so I do sense some tolerance of dry conditions.
Balloon Flowers have a very fleshy root system, and do not like to be disturbed. I like to plant them near the front to middle of the bed; too far back, and you don't appreciate how classy the stems and leaves are. Most books point out that if you do lift and divide them, they won't bloom for up to two years. I lifted and divided mine several times, and all divisions bloom heartily the following year, but what do I know.
I like BF as a specimen plant, that is, a clump by itself, for accent. It just doesn't lend itself to massing, or planting in waves. I don't know. You try it the way you want. But I like it lean. I look at Balloon Flower in my garden and am reminded of Audrey Hepburn, by herself in the rain, in that scene at the end of Breakfast at Tiffany's.
Balloon Flower combines well with daylilies (grow a later-blooming yellow or gold daylily with BF), and just about everything that's blooming in the same period, especially tall phlox. My BF sits in front of the tall pink phlox blooming right now, and the combination is pretty darn perfect, covering all the bases, color, contrasting forms, nice contrast in bloom size, you name it.
Best of all, BF is hardy as granite. Zone 3 is a snap, as is Zone 2. Balloon flower is slow to emerge in the spring, so mark it in the fall or you'll forget exactly where it is.
I've just written
an eleventh tenet of Renegade Gardening: When you give out gross
misinformation on your Web site, admit it. Plus a twelfth tenet:
When forced to impose the eleventh tenet, blame the neighbor
who gave you the misidentified plant.
Actually, Dave's not at fault. I just want to thank the good folks at the American Bamboo Society who visited the site, huddled, e-mailed me a few more questions, huddled again, then notified me of their findings: that's me in the picture, all right, but I ain't standing within a hundred miles of bamboo.
Yes, you've been bamboozled (as if I could resist that one). Please go easy on me. It's not like I asked you to slip into your Nikes and wait for the comet.
What we got in the picture is Polygonom, that may or may not have the common name Japanese Knotweed (I'm not taking any more chances). The head of the northeast chapter of the ABS sent me a list of eight reasons the plant pictured could not be bamboo (Phyllostachys), from leaf size (too large for hardy bamboo) to stalk texture (would be brittle, this stuff isn't) to growth characteristics (the plant in the picture—my rare Jap Knotweed—reaches its height in about eight weeks. Northern bamboos only grow up for three weeks, then out for the rest of the season).
But some cool stuff has resulted. Yes, there are a couple of bamboos we can grow in Zone 4. And as a new member of the NE Chapter of the ABS, I'm getting one in the mail!
My apologies for the misinformation. Do check this link to the ABS to find out more about hardy bamboo. And keep an eye on me, will you?
Lobelia cardinales (low-BELL-ee-a
card-ih-NAHL-ess)
Common Name: Cardinal Flower
Here's a striking
native perennial that isn't included in nearly enough northern
gardens, particularly when one considers that with proper care
and culture it's hardy to USDA Zone 2.
Lobelia offers an extremely uncommon appearance, and lends a stately, sophisticated air to the proceedings. The top eight inches of the prominent main stem(s) is covered with small spikes of brilliant, rich red flowers from mid- to late summer; the plant always draws comments from visitors to my garden.
OK, so it's not the easiest plant to grow. That doesn't make it difficult. It's enough, however, for many nurseries and garden centers to place it in their "One Dead Return Too Many" doghouse. So you may have to order it via the mail (check out my column Best Minnesota Perennial Growers; virtually all offer mail-order). But you, comrade, can grow Lobelia. It simply involves gardening.
Care and Use: A woodland plant, Lobelia grows in sun to part shade and reaches heights of four feet. It prefers soil high in organic matter and likes to keep its feet wet, so one use is along natural streams and ponds, as well as beside the water garden. Amend the soil by adding plenty of compost and/or peat moss, plus coarse sand or pea gravel to ensure decent drainage. If no water setting is handy, use it at the back of the perennial bed just as you would tall phlox, then remember to water it twice a week (comparable to Astilbe or Ligularia) during periods of no rain. Provide a mulch in the summer to retain moisture.
Concerning its reputation for not lasting more than a year or two, preparing the soil as described above and not allowing it to dry out completely (gardening) will do much to improve its longevity, as will dividing it every year. Lift the plant in September after bloom, remove the outside clusters of new basal growth, and replant them in rich soil. Water them in and keep them moderately moist until frost. Mulch the "mama" plant and her babies with a good eight inches to a foot of marsh hay or bags of leaves after the ground freezes. The plant also self-seeds readily, so in combination, you should have plenty of nice specimens around each year.
A blue variety, L. siphilitica, is less demanding to grow, and takes more of a bush form. But Prince didn't name his song "Little Blue Corvette." Red, as all humans know, is where it's at.
Annuals that don't look like annuals
rank high in my book. Did I tell you that 2000 is the Year of
the Zinnia? Of course I didn't. Yet it is—says so right
here in a fancy press release I received from a very self-serving
national nursery group of annual growers. I think I was supposed
to pass this important news along to you in January. They sent
me all sorts of color pictures; tall zinnias, short zinnias,
red zinnias, orange zinnias, bi-colored zinnias.
Problem is, I hate zinnias. I tried them once, in a big way, and realized halfway through the season that they look goofy in a perennial bed, a loud gang of Mexican cowboys crashing the prom.
A minor, little-known annual such as Hypoestes won't be touted by this group for as long as we're alive, because the nursery industry doesn't think gardeners will show much interest in an annual with wonderful form and knock-out variegation. I use this breathtaking marvel at the front of the bed, anywhere I need a sexy pink come-on to break up the border and provide relief from flower blooms. The plants in the photo had just come home from Lynde Greenhouses in Maple Plain, one of the better annual growers in the Twin Cities, and one of the few places I've seen Hypoestes. With pinching, they'll grow lush and full of leaves; I keep them at around 18 inches.
Care and Use: Plant in full sun to part sun (mine get 4 hours and do fine) at the front of the bed in good garden soil. Use at least five plants, spaced 8 inches apart in the north. Fertilize two to three times during the season. Combines well with anything and everything. You will have a difficult time planting these and not have them look great.
Campanula glomerata (kam-PAN-you-luh - glom-er-AH-tah) Common Name: Bellflower, Harebell
Thought I'd better
start living up to the advertising on my Home Page and recommend
a Zone 2-8 genus for all my fine visitors from mountain regions,
the extreme northern U.S., and those areas in Canada that I'm
certain are friendly, picturesque, wonderful places to live,
but astonishingly cold in the winter.
I get a little giddy about Campanula. It remains to this day one of my all-time favorite perennials in flower. C. glomerata 'Superba' is just about everywhere in my gardens, since it blooms rich violet-blue in full sun or part shade, flowers in June before most perennials have showered and shaved, combines well with just about everything, and spreads like a weed.
Campanula comes in quite a variety of forms. C. carpatica is well-suited to the rock garden with a mere 6-12 in. height and blue, cup-shaped flowers. C. persicifolia offers spikes of blue flowers and height up to 3 ft. 'Superba' grows to 24 in. and stops the traffic on my road when in bloom, due to its clusters of bell-shaped flowers alternating between leaf nodes from top to bottom. A different variety of C. glomerata features white flowers, but white flowers are a dime a dozen; few perennials give you a blue like this.
Some books list this plant as hardy Zones 2-8, others Zones 3-8. Truth is it is very hardy (with proper care during the growing season) as far north as Zone 3, with good success in Zone 2 provided you start with healthy, well-bred plants and provide good winter mulch, such as 8 inches to a foot of marsh hay.
Care and Use: This plant is going to own the show in June, so stick it where people are going to see it, midway in the flower bed, but avoid the front. The only flaw to the plant is that it brings nothing to the party after it's done blooming. After the first bloom, deadheading it will extend the color into July, but after that it will have no form or value in the bed. Cut it down to the mound of fresh basal foliage and let it build up more roots for next year. Plant a wave of at least three plants behind some later-blooming plants, so they hide the mounds the rest of the season. You can also plant a mid-sized annual, such as salvia or the taller snapdragons, in front of the mounds to hide them from view.
Does best in full sun but mine look great with only four hours of direct sunlight. Campanula can take heat and dry periods but rots out in overly moist soil. After blooming, I treat it like an iris, and water it sparingly through fall. NEVER CUT THE PLANT DOWN IN THE FALL. Next spring you will be rewarded with a good number of new plants as far away as 8 in. from the mother plant. Divide in early spring or mid-fall.
Boltonia asteroides
Common Name: Snowbank
I grow boltonia
all over my property, but it was the act of digging out a
huge clump this afternoon, carefully dividing it, then throwing
all of it on my new spring compost pile that made me realize
‘Snowbank’ was the perfect plant for the Spotlight.
That’s right, the compost pile. Sacrilege? Not when you own boltonia. This week, go out and buy three small pots of the stuff, plant it in any type of soil, grow it in full sun or part shade, water it properly or forget about it, fertilize it or don’t, and no matter which path you choose, about five years from now you’ll be in the nursery business, specializing in boltonia.
It is the perfect perennial. It spreads out quickly after the first year, but is polite about it. The clumps get bigger and bigger, tripling in size each season, but in a non-invasive way. (Seriously. It’s hard to explain.) The clumps don’t die out in the middle, either, they remain full, which means that after four or five years you can have a stand of the stuff that covers ten square feet, easy. And that’s from one plant-you bought three, remember?
Quick to emerge in spring, ‘Snowbank’ just gets taller and taller all season until fall, when tiny clusters of snow-white flowers fill the plant nearly from head to toe. Narrow leaves and prominent, singular main stems mean that it’s not the most captivating plant in the ol’ arsenal during the summer growing season, but when it blooms in September, oh my.
Care and Uses:
Plant at the back of the border or center of island beds. Performs
best in full sun, but my plants bloom very well in only three-and-a-half
hours of direct sun per day. Can be cut in half in mid-June if
you’d like even more bloom and a shorter plant at bloom
time, but I’ve never staked it or had any problems with
it falling over, even when in bloom at 48 inches tall. Combines
very well with virtually all the Zone 4, fall-blooming perennials,
particularly the medium and tall asters and mid-sized sedums,
such as ‘Autumn Joy.’
Alchemilla mollis
(al-keh-MILL-uh moll-iss)
Common Name: Lady’s mantle
Color, shape,
texture, form — these are the buzzwords that gardeners slowly
come to understand as the important components to pleasing garden
design. Plants with uncommon shape and color to the flower, uncommon
texture to the leaves and different overall form from most other
Zone 3 & 4 perennials can’t miss in the garden. Welcome
to the genus of plants named Alchemilla.
Chartreuse(!) flowers emerge in early to midsummer, barely hovering over soft, lobed, tufted, light green leaves. The plant by itself provides pleasing contrast of color. Mounds to a height of 12 in. to 15 in., with a spread to 24 in. It does well in my shady yard, where three of them are planted in an “L” at the entrance to a narrow stone path. Receiving only three hours of direct sunlight per day, light shade for the rest, they bloom readily. Individual flowers are tiny, star-like, dancing in clusters above the highly attractive foliage. Nothing else in your garden looks like Lady’s mantle.
Use and Culture: plant at the front of the border in partial shade to sun. Space 18 in. apart and be prepared to separate them further the second or third year. Leaves can scorch in full sun conditions (eight hours or more). Not terribly picky about soil, but won’t grow in overly-moist, boggy conditions. Requires removal of withered/brown leaves from time to time during the season. Responds fairly well to deadheading as blooms fade. Shear in mid-August to expose the new, lush basil growth you will find underneath. Do not cut down in the fall. Self-seeds. Very soft and cuddly in appearance, the plant contrasts well with boldly vertical, tough-looking perennials such as Iris or Liatris spicata. Zones 3-8.
I
don't often jump on the bandwagon of brand-new All-America Selection
winners, preferring instead to sit back and watch a few seasons
to see which of these always highly touted specimens actually
live up to their pedigree once handed the ball. But this new
Cosmos is so brazenly trashy, I'm giving it the go-ahead as front-runner
for rookie of the year honors.
Three things in its favor. First, even though a Cosmos, the hybridizers have for once done us all a favor by shortening this one up considerably. It's going to top out at 22 inches, meaning there's no staking necessary.
Second, its flower form is like that of a number of Zone 2-4 perennials. I like annuals that look like perennials; their use with perennials create better-looking flower beds. (Plant a swath of pansies as the front edge of an otherwise perennial garden if you want to see what I mean).
Third, and turning our attention specifically to 'Cosmic,' it's ORANGE, for god's sake, screamingly, drunkenly, terminally orange (color at right may vary depending on your computer). Take that, you Puritans (see full version of RG Tenet #8).
Use and Culture: Plant in masses (5 or more plants) in the center to front of the garden. Take a whack at using one in a really big container. 2-inch double and semi-double blooms early summer to frost if properly deadheaded. True orange combines well with blues (particularly light blues), greens, even yellows for the daring, but watch out for the reds and certain pinks and salmons in close proximity. Give you a headache. Cosmos need full sun — 6 hours minimum, 8 or more preferred. 'Cosmic Orange' will do well in almost any type of soil. Actually likes it fairly infertile — do not amend soil except for better drainage. Sow seed directly into garden after final frost. Seeds available now in many catalogs, should find it as a bedding plant in May at nurseries.
Eupatorium rugosum 'Chocolate'
Common Name: (White Snakeroot)
I
can't understand why last year was the first time I brought this
magnificent perennial home. Never grew it before, finally got
around to trying it, I enjoyed its chocolate brown foliage all
summer. Then 'round about mid-September, it greens up and sneaks
into bloom and just stole my heart. Not flashy, but poised and
serene. Bloomed straight through to December 10th — the
first hard frost in my yard. My three plants were tucked off
to the side of a garden bench, and in a quite shady spot amidst
cedar trees they topped out at around 3 feet. The flowers are
small, domed, and nearly pure white. Looks oddly native. A true
gentleman of a plant.
Use and Culture: Plant in masses (3 or more plants) spaced 18 inches apart, in part sun to shade. Prefers well-drained soil amended with organic matter. I can't think of another comparable-looking, fall-blooming shade plant, meaning it mixes well and provides contrast with many, many shade favorites. Last summer I had fairly major disease and pest problems with a lot of my plants, yet 'Chocolate' remained completely unscathed. Available at better growers, check my column Best Minnesota Perennial Growers.