- Indiana Yard and Garden - Purdue Consumer Horticulture

Q. I have some questions about a ‘Rose of Sharon’ bush I have, which was damaged in the ice storm that we had last winter. I was wondering when would be a good time to trim it, how far back should it be trimmed and how often. Thank you ever so much. — Barbara Huse

A. Since plants bloom on new growth, shaping or pruning can be done at any time. Pruning in late winter or early spring is a typical practice in Indiana. Rose of Sharon is e asily grown in average, medium wet, well-drained soil in full sun to part shade. It will flower best in full sun. It prefers moist, organically rich soils, but tolerates poor soils and some drought, and is tolerant of summer heat and humidity. You can get large flowers by pruning back hard to two to three buds in early spring. It can also be pruned into a small single-trunk tree form or espaliered!

Q. You previously mentioned using green organic mulch in your column. Anytime you use a green mulch with a high-moisture content, such as fresh lawn clippings (if used around living plants in any appreciable thickness — say an inch or more deep), be sure to keep a space of mulch-free, open air clear around each plant to avoid “burning” the living plant stems. All fresh green mulches will go through a period of really “hot” natural heating as the mulch starts to decay and deteriorate . If such mulch is snug up against the living stems, it will burn a black “collar” clear around the stems . It’s disastrous.

Maybe it has never happened to you, but it sure has to me, and through that one experience I will never forget it! Many years ago, just before our family left for a two-week vacation or so, I placed fresh lawn clippings close around all our geraniums to “hold” the weeds and retain moisture while we were gone. When we returned, I couldn’t help but notice how sick-unto-death they all looked . Pulling the mulch away, I could see a three-fourths inch thick or so burned black band clear around each stem. I had killed them all! Lesson learned! — William P. Martin, Lafayette , Ind.

A. Plants can indeed be damaged by thick layers of grass clippings. Take particular care with green, herbaceous stems, which are more tender than a woody tree trunk.

Generally, all mulches should be kept away from the stems themselves. Even “dry” mulches, such as shredded hardwood bark or dried pine needles, should not be piled around trunks or stems. They provide shelter for rodents during the winter and increase the likelihood of rodent damage to the plants.

Q. These beautiful flowers (photo enclosed) grow along ditch banks. They bloom in mid-August usually. Could you tell us what they are called? — Austin and Lora Bapple , Wheatfield , Ind.

A. They appear to be cardinal flowers (Lobelia cardinalis ). Cardinal flowers bloom in late summer in low, moist areas, including ditches, stream banks and marshes. These native intense, red spires attract ruby-throated hummingbirds.

Cardinal flowers can be grown in full sun or very light shade but grow best in filtered light. Mulch to keep the roots moist. This tends to be a short-lived perennial but will self-seed, so don’t deadhead the spent blossoms.

In my opinion, the perennial world is heavily weighted toward yellow flowers, and there are far too few reds. Cardinal flower is a great addition to the garden if you have the right conditions.

Q. Three years ago, I planted a Harry Lauder’s Walking Stick. This year, all the new growth has been straight. What can I do? — Yvonne Hock, Madison , Ind.

A. Suckers will often appear from the base of the plant, and it’s good to prune these out. The straight-stemmed pieces are more vigorous than the contorted one and can overwhelm the plant. Since you’re growing it for it’s unique, twisted stems, you’ll want to avoid allowing the straight stems to gain a foothold.

Interestingly, Lauder was one of Britain ‘s most celebrated music hall comics/singers in the early 20th century and is still Scotland ‘s highest-selling recording artist of all time. His stage presence relied on his kilt and curly walking stick, for which the plant is named.


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