In the latter part of the growing season, many of the native perennials (forbs and grasses) are naturally taller in height. Extra rainfall also grows taller perennials, and then wind storms can cause taller perennials to fall over. In a newer native garden, taller plants might lean because there are no other plants close by for support due to spacing. Because Illinois is the land of the tall grass prairie, I urge everyone to embrace our taller native perennials. Here area a few tips and solutions for dealing with taller native perennials in your garden.
- For shorter groups of plants (5′ or less) leaning onto walkways, paths or other areas: Use 2-3′ foldable wire fencing along the edges of the pathways. See photo below. Purchase this fencing at any home improvement store or garden center. You can often get this fencing on sale at the end of the season and you’ll be ready for next year. This type of fencing is barely noticeable since the plant foliage will conceal most of it.
- For taller groups of plants (5′ or more) leaning into walkways or paths: Place 4-6′ bamboo stakes or poles with natural jute twine fencing along the garden edge. I have a pretty tall prairie garden in my side yard, so I have used 6′ bamboo stakes along both sides of the path going through the garden. I initially spray painted my bamboo in shades of blue and turquoise, then polyurethane so the stakes are more decorative and last longer outdoors. I set the poles at 4-5′ intervals along the path, and pushed them about 6-8″ into the ground. It’s best to insert them when the soil is moist, since clay soils are as hard as concrete when dry. Then I took natural jute twine and tied it securely about midway in height to the first pole in my path, and then pulled the string taut, and wrapped it 3 times around the next pole, then pulled it taut, and continued until I reached the last pole, then tied it securely. If needed, you can tie another layer of string further down or higher up, depending on how much support you need. The twine is barely noticeable since most of the plant foliage will conceal it. See photos below.
- Use 3′- 4′ bamboo poles and jute string to stake individual plants, adjusting the string and poles between the foliage to hide as much of it as possible. You can use 1 bamboo pole for smaller plants or 3 poles in a triangular configuration around larger plants. I really like some of the stakes and supports sold by Gardener’s Supply Company. I recently purchased 66″ tall stem ladder support to hold up my 10′ tall Compass plant stems knocked down by a recent wind storm, and they work great!
- Be patient – Wait until the plants fill in. It took about 6 years for the plants in my prairie garden to fill in so that most of the plants support each other, except at the outside edges of the garden, where there is either a mulch or lawn path. I planted my garden using plugs about 1.5′ apart, If you start your garden densely from seed, the garden will probably fill in much sooner.
- Cut down some of your tall plants. I have no qualms about cutting back a few of my taller plants leaning across a path, although I only do this as a last resort after I have used one of the methods above. I won’t trim plants that are not as prolific in my garden like Rattlesnake Master. Instead I stake them up if needed.
- In late spring – early summer, try trimming or cutting back later blooming plants like: Aster, Monarda, Boltonia, Echinacea, Eupatorium,Heliopsis, Physostegia, Rudbeckia, Solidago, Campanula americana, Rudbeckia to about 1/3-1/2 in height once or twice before midsummer. Cutting back these plants will delay their flowering time and reduce their height. Leave some uncut, to stagger flowering time and height. This method doesn’t work for all perennials. You can also cut back some of your spring -early summer blooming plants right after flowering like r, Spiderwort, Wild Indigos, Canada Anemone, and the ones listed above to prevent them from leaning after flowering. They may re-bloom.
- Do not compost, fertilize, over mulch or water established native perennial plants. The extra moisture and rich soils will cause plants to lean. 1″ of finely shredded mulch is all you need around perennials initially but please pull mulch away 1-2″ from plant stems and leaves. If you cannot keep up with weeding, add more plants or seeds so plants will fill in quicker and support each other. One last tip: Sometimes native perennials which prefer more sun, lean toward the sun if they are in too much shade.
Right now I have twenty flower stalks on my Prairie Dock that are 12′ tall and are ready to pop open. I cannot wait! Please share your tips on how you handle tall perennials in the comments section below. Thank you.