Hollyhock rust, fire blight, reminders

By John Fulton

[June 20, 2013]  Hollyhocks are one of the traditional, old-fashioned flowers often grown in our area. This year, they are definitely interesting. Even before the flowers open. Most area hollyhocks are infected with rust. Rust is usually a spring and fall disease problem, when it occurs.

Rust first shows up on the bottom of the lower leaves, and the top side of the leaves develops some rather striking bright yellow to orange spots. Rust can attack all plant parts, including leaves, stems and leaf petioles.

The rust disease spends the winter in old plant parts on the ground, so removal of the plant material will help reduce infection possibilities. Increasing air flow and reducing humidity will also help. Control is best accomplished by removing infected leaves at the first sign of the rust (on the bottom of the leaves). Chemical control may be needed, and sprays containing sulfur are effective. Also effective at preventing new leaves from being infected are many of the protective fungicides.

Fire blight

Apple and pear trees continue to have their problems. There is a large amount of tip dieback in some varieties, and this is probably fire blight. Look for a shepherd's crook at the tip of the affected areas as a clue it is fire blight. Fire blight is a bacterial disease; therefore, there is little chance for you to treat it.

The common treatment in commercial operations is streptomycin, but it has to be applied before symptoms appear. If you are lucky, you may be able to find these products in the better-stocked outlets. In some years, Bordeaux mixture can also help prevent the disease -- and that means prevent and not cure. The disease is also hitting the ornamental pears rather hard in some years.

Reminders

We are now in the middle of the correct planting time for the warm-loving vegetables for our gardens. This would include lima beans, cucumber, eggplant, melons, peppers, summer squash, winter squash and pumpkins. Pumpkins for use as fall ornamentals should be planted now for fall display. We're at the proper timing for fall garden plantings for potatoes, kale and some others. Some of the planting dates overlap this time of year. That basically means plant it, but you can expect harvest to be closer to fall.

Keep pruning flowering shrubs after they complete bloom. That will allow for more flower buds for next year. Also, start pruning evergreens at this time.

[By JOHN FULTON, University of Illinois Extension]