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

February “In The Grow”

Q. I had a severe problem with black spot on my roses last season. What can I do, and what can I use to prevent it this year?
–Ruth A. Beer, Syracuse, Ind.

A. Black spot is a serious problem on roses in Indiana. Black, circular spots with fringed or uneven margins form on upper leaf surfaces in the spring and summer. Spots may also develop on canes and leaf petioles when the infection is severe. Infected leaves eventually yellow and drop prematurely. Some canes can become completely defoliated, which can weaken the plant and predispose it to other infectious and noninfectious problems.

Prevention of black spot is helped by garden sanitation, since the fungus overwinters on rose canes and fallen infected leaves. Spores are splashed onto new leaves throughout the growing season. Rake and destroy infected leaves, prune to open up the center of the plant and avoid overhead watering when possible.

Rose cultivars vary quite a bit in their susceptibility to black spot. When purchasing new roses, look for cultivars that have some resistance.

Black spot is caused by a fungus that thrives in wet conditions so infection takes place primarily in May and June. This is when fungicides are needed to prevent black spot. There are several commercially available rose fungicides that provide excellent control (as with any fungicide, check the label to make sure roses are listed). Read and follow label directions, especially concerning repeated applications.

Q. With the recent deep snows, a herd of deer came down from the hills behind our home and invaded our quiet neighborhood. They ate all the green foliage from our arborvitae and yews, plus any leaves that were left on our various bushes. After years of care, they all looked so nice. I hate to think that I have to dig them out and start over.
–Paul Roembke, Pierceton, Ind.

A. The deer are more challenged to find food with snow covering the ground this winter. That means they’re moving out into new territory and will brave the risks of suburbia for a tasty arborvitae. Unfortunately, many evergreens that have been completely defoliated will not recover, although yews have latent buds and will put out new growth. They’ll look scraggly for awhile, though! The other assorted bushes may respond better to this unplanned pruning, depending upon the species.

Many attempts have been made to rid gardens of deer. An option called polytape or an electric peanut butter fence is the most effective method. Full details on cost, construction and effectiveness are available from your county Extension office, in Purdue Forestry and Natural Resources bulletin FNR-136 or online at http://www.agcom.purdue.edu/AgCom/Pubs/FNR/FNR-136.html.

Several repellents are available that deter deer with their scent, or you can make your own at home with two eggs, one cup of nonfat milk, one cup of water and two teaspoons of a spreader-sticker. Whirl it up in your blender, and spray it on your plants. The scent of rotten eggs will keep deer away (and friends and family, probably) but must be reapplied after rain. Remember, if the deer have nothing else to eat, they’ll eat food that smells like rotten eggs.

Finally, a dog in a fenced yard can do wonders to keep the deer at bay. Make sure you really want a dog first, though!

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