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Physocarpus
July 5, 2012
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Going to Drought School – Class of 2012
August 31, 2012

Big Perennials for Big Kids

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Big Perennials for Big Kids

I like cute little plants like ‘Firewitch’ Dianthus and ‘Lucerne’ Blue-Eyed Grass. I also like plants that have an airy texture like Prairie Dropseed or Switch Grass. I just love the subtle beauty of Musclewood flowers, these tiny jewels of color that few take the time to see. What I really like though, and I mean in the same way ice cream fits into my food world, are the big perennials. I love the perennials that get huge, the ones with flowers at eye level, the ones that I can almost hear growing in May and June and those with leaves that are bigger than my head.

Big plants are impressive. I remember growing delphiniums (see feature image) as a 12-year-old kid along the front of our garage. I felt an incredible sense of accomplishment when those flowers were nearly as tall as me. Kids love big plants. What kid doesn’t like huge pumpkins or sunflowers? They all do. That’s why big pumpkin and sunflower contests are so popular. It’s important to impress our kids with plants. Being the big kid I still am, I have never gotten over the thrill of growing large plants. Here are some of my favorite big perennials:

Featured Image Caption: Me, the cat, and my huge delphiniums in 1968. Notice I wasn’t much for weed pulling.

Giant Fleece Flower
Persicaria polymorpha

This is a rarely used perennial that grows 4 to 6 feet tall and 3 to 4 feet wide. At the nursery we have three plants that are performing beautifully in a display bed in partial shade where they get afternoon sun. Clients comment on them the entire time they are in bloom, which is typically in June and July. They have a very long bloom period, usually a month or more. The creamy, white flower clusters are up to a foot long and 8 inches wide. Just like the plant itself, they are huge! I have not observed any insect or disease problems on this plant.

Giant Fleece Flower has clean, tear-drop shaped leaves that can get up to 8 inches long and 3-1/2 inches wide, though it has many sizes of leaves on the plant at the same time. It has hints of yellow to the foliage in the fall, but usually freezes before it can completely turn color. It is related to the very invasive Japanese Knotweed, which is an extremely destructive plant in Wisconsin’s natural ecosystems. However, I have never heard of nor seen Giant Fleece Flower seed in the garden. It is a clump-forming plant and doesn’t run like its evil cousin. Persicaria polymorpha is a wonderful plant!

big perennials persicaria polymorpha giant fleece flower

Left: Giant Fleece Flower is 6 feet tall at Johnson’s Nursery | Right: In #5 container

Queen-of-the-Prairie
Filipendula rubra

Filipendula rubra is a wildflower that grows in moist soils, typically along rivers in the upper Midwest as well as in fens and moist, sandy prairies. It is not considered native to Wisconsin but is found just across the border in northern Illinois. Queen-of-the-Prairie is said to get 3 to 6 feet tall. My experience with them says their height is closer to 6 feet than 3 feet. The flowers on this plant are spectacular! Cotton candy-like, pink puffs of bloom appear on long, naked stalks in mid-summer. The flowers have the texture of Astilbe flowers. The inflorescence shape differs from the pyramidal Astilbe in that Filipendula has a V-shaped outline, being wide at the top and narrow at the bottom. The flowers vary in size somewhat from one to the next. The inflorescences are most commonly about 5 to 8 inches tall and 3 to 6 inches wide. The flowers don’t have a fragrance and do not provide nectar to insects, though they do attract pollen-gathering bees.

This plant has no major disease problems. Because it likes to have a good moisture supply, it does not hold up well in drought unless it is given supplemental water. Queen-of-the-Prairie is an excellent choice to use along the side of a pond, stream or in a rain garden. It should be planted in full sun or partial shade and be given plenty of room to spread. It slowly suckers, but not in an overly aggressive way. Few plants can match the royal beauty and grace of Filipendula rubra - truly deserving the title of Queen-of-the-Prairie.

big perennials filipendula rubra queen of the prairie

Left: The incredible flowers of Queen-of-the-Prairie | Right: Filipendula rubra in a man-made prairie

Gateway Joe Pye Weed
Eupatorium maculatum ‘Gateway’

Joe Pye Weed, like Filipendula, is a wetland plant. It is native in a large area of the eastern United States and ranges into the swamps of Wisconsin. According to North Creek Nursery, the plant is named for Joe Pye (or Jopi), who, according to folklore, was a traveling Native American medicine man. He lived in New England around the time of the American Revolution and may have been from a tribe in Maine. He sold various herbal remedies to the colonists and apparently treated typhoid fever with the plant that bears his name to this day. The cultivar ‘Gateway’ is a slightly shorter growing form that is said to reach 4 to 5 feet, though I remember seeing it at eye level in a trial at the Chicago Botanic Garden a few years back (I’m 6 feet, 1 inch tall).

The plant usually blooms in late July or August in our area, producing huge panicles of mauve-pink flowers. Some inflorescences will get over a foot in diameter and contain over 150 individual flowers. Like all of our native Eupatoriums, ‘Gateway’ is a butterfly magnet, attracting as many butterfly species as the much more publicized Buddleias (Butterfly Bush). Tiger Swallowtails love Joe Pye Weed. Eupatorium maculatum is also host for the larvae of nearly three dozen moth and butterfly species. This helps numerous bird species that rely on the caterpillars to feed their young. If you like wildlife, the giant ‘Gateway’ Joe Pye Weed is a must have plant.

big perennials eupatorium maculatum gateway joe pye weed

Left: Eupatorium maculatum ‘Gateway’ in bloom | Right: 'Gateway’ in a #5 container

Hosta ‘Sum and Substance’

‘Sum and Substance’ is a monster of a Hosta. It has chartreuse leaves that grow to 15 inches long and 12 inches across. The plants themselves develop into clumps that can be 5 feet wide and 30 inches tall. Lavender flowers develop on 3 feet long stalks in mid-summer. This hosta makes a bold statement in the shaded landscape. It is especially effective when used in combination with big masses of fine textured plants such as Lady Fern or Sweet Woodruff. The thick leathery leaves of ‘Sum and Substance’ give it a high degree of slug resistance and allow it to tolerate some direct morning sunlight.

Large perennials are traditionally sold in #1 container sizes. This is not the best size to purchase. These big plants need big containers to thrive and develop into healthy specimens. They become stressed and stunted in containers that are too small. Big perennials have the presence of a shrub and are most effective when installed from #2 or larger containers. In the garden center, the larger containers help the clients better understand the scale of the plants upon their first encounter with them.

At Johnson’s Nursery, many of the big perennials are produced in #2, #3, or #5 containers. This allows designers to use the plants in a manner similar to what would be done with shrubs. Proper spacing can still be allotted for each plant and the client doesn’t have to wait to see the visual impact. It puts the perennials in scale with the rest of the landscape.

Many of these big perennials are especially useful in areas where substantial plant mass is needed, yet snow will be piled in their location during the winter. Because they die to the ground in the fall, there is no need to be concerned about branches breaking as would be the case if a shrub were used.

Big perennials can really be a lot of fun to work with- whether it’s for their fast growth rate, huge dimensions, or magnificent flowers. Grow a few and I’m sure you’ll feel like a kid again!

big perennials hosta sum and substance

Hosta ‘Sum and Substance’ is large enough to hide a 6 feet, 1 inch tall kid!