April "In The Grow" - Indiana Yard and Garden - Purdue Consumer Horticulture

April “In The Grow”

Q. I’ve been out in the backyard giving myself a backache chopping down ornamental grasses. We love them 363 days a year; every day except for the two that we spend chopping them down and getting rid of the debris! Any thoughts? – Amy Raley, West Lafayette, Ind.

A. We buzz down our ornamental grasses with electric hedge shears and a chain saw. The task goes by quickly! We leave the dried grasses in place for most of the winter so we can enjoy them as they wave in the breeze. It’s time to cut them back if a wet, heavy snow load starts to break up the stems. They look bedraggled once they’re bent, and it’s hard work to pick up the individual pieces if they’re strewn across the yard.

Our grasses held up well this winter, so we left them until a reasonably warm weekend in early March and then cut them off 6 inches from the ground. Don’t put it off any later than early April since some of the cool-season grasses grow quickly in early spring. Once new, green growth is mixed with the brown stems from last year, you’ll never get it sorted out!

Q. Last year, my tomato plants first got the big, green worms, but I was able to get rid of all of them. Next, my leaves turned brown. I removed these. My vines were skimpy, and the tomatoes were small. I have been advised not to plant tomatoes on the same ground this year. I only have a small space for planting. Is there something I can do to the ground to kill the blight? I was told Ortho has a product. Do they? – Jean Lowden, Angola, Ind.

A. Several tomato afflictions cause brown leaves, including late blight, fusarium wilt, verticillium wilt, bacterial canker, and improper watering and fertilization practices. You don’t want to start using pesticides without a definite diagnosis, especially since there is no chemical control for fusarium and verticillium. Ortho used to recommend a product that is now a restricted product and requires a licensed applicator.

Anytime that you have trouble growing a plant, it is wise to rotate the crop out of the area. Perhaps you could rotate the immediate area where tomatoes grew last year to another crop and grow the tomatoes in containers this year. The easiest way to handle the problem is to make sure your tomatoes are resistant to verticillium and fusarium. This is denoted by the letters V and F following the cultivar names. For example, you might plant Beefeater VFN, which tells you it is resistant to verticillium, fusarium and nematodes. If you continue to have trouble, bring samples to your county Extension office.

Q. I have trouble winterizing tender perennials like rosemary and scented geraniums. I bring them indoors in the fall in the same containers that they grew in over the summer. They go in my “plant room” with my houseplants. The room has eastern exposure. By January, the winterized plants are either dead or close to it. What can I do to save these plants? My houseplants do fine. I live in NW Ohio in zone 5. -Janet Shoviak, Waterville, Ohio

A. Your houseplants are acclimated to the low light levels of our Indiana homes, but that rosemary wants to be on the sunny banks of the Mediterranean. A southern window would be best, but any window will benefit from supplemental light. Fluorescent fixtures with cool-white bulbs should be placed 1-2 feet above the tops of the plants. Leave them on for 12-16 hours per day.

Q. I have three hydrangea bushes, and they have only had about three blooms on them. Do I need to cut them down in the fall or let them stand until the leaves fall off? – Malinda Clark, Washington, Ind.

A. Different hydrangeas require different treatment. Bigleaf hydrangea cultivars (Hydrangea macrophylla, which usually have blue or pink flowers) bloom on last year’s wood. That means the flowers can be removed but the branches must be left in place to have any hope of getting flowers. This is usually pointless, since our Midwestern winters usually kill the tops back to the ground. When it is obvious if the top has been killed back in the spring, you can cut the branches off but expect no blooms that year. This plant frustrates many Indiana gardeners. Oakleaf hydrangeas (Hydrangea quercifolia) flower on old wood but are hardier and the tops often survive the winter. The flowers can be removed anytime, but the branches should be left in place.

If you’re lucky, you’re referring to the smooth hydrangeas (Hydrangea arborescens with white flowers). These plants flower on new wood and can be cut back at several different times. Once the flower has turned tan, you can cut it off and use it in dried arrangements. This may even cause the plant to flower again during the growing season. Or, if you like the interest the dried flower provides on the plant, you can leave it in place and cut the entire plant down to the ground in the fall or winter.

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