Hollyhock rust, evergreen pruning, to-do list

By John Fulton

[July 10, 2012]  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 again infected with rust. Rust is usually a spring and fall disease problem, when it occurs. This year it has been ferocious.

Rust first shows up on the bottom of the lower leaves, and then some rather striking bright yellow to orange spots develop on the top side of the leaves. 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. Removal of the plant material will help reduce infection possibilities, so remove dried, infected leaves now. 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.

Pruning evergreens

This is the time of year to wrap up pruning chores on evergreens. This includes both needle-type and broadleaf evergreens. If you're wondering what a broadleaf evergreen is, that includes holly, rhododendron and azalea. The logic behind pruning your yews at this time is to allow sufficient time for regrowth to become hardened off before winter and to keep new growth from becoming too rank before the winter months.

Pruning evergreens is part art and part science, but mostly art. A few simple rules to follow make the job results much more pleasing. Upright-growing evergreens, such as pines and spruces, should not have the main leader cut off. This will destroy the natural shape and will make the resulting growth more susceptible to breaking off. If individual branches are being cut off, they should be cut back to a bud. This will allow the bud to become the new main branch. You can also control growth direction of branches in this way. If you are growing trees for cut Christmas trees, all bets are off, as you are only dealing with trees through the first seven years or so of their life.

Make sure you use the proper equipment. Individual pruning cuts are best done with bypass loppers or pruning shears. These make clean cuts without much damage to the remaining wood. The old anvil-type shears and loppers cut to a point, then crush the remaining wood. For yews, junipers and arborvitae that are trained to a certain size or shape, you will want to use hedge shears (electric or manual) that are sharp and properly tightened. Most of these types of shears can cut up to about a quarter of an inch in size.

When pruning evergreens, remember the dead zone. This is the area toward the center of the plant that doesn't receive much light. It also has few needles or active buds. Cutting into the dead zone will cause many years (or forever) of little green growth. Also remember to prune so that the base of plants is wider than the top. This allows sunlight to hit the bottom area as well, and keeps plants from browning from the bottom up.

To-do list

• Keep up with, or start, foundation sprays. The common products are permethrin or bifenthrin. Apply them to the foundation and adjacent foot of soil, flowers, etc. This will put down a barrier for insects such as ants and crickets.

• Keep a good spray or dust program going on your cucumbers, pumpkins, squash and melons. This will help control vine borers and beetles that carry the wilt virus.

• Check tomatoes for the fungal diseases such as Septoria. If spots are on the leaves, you will need to apply a fungicide to halt the progress. Fungicides available include chloranthanil and maneb. Also, check for leathery bottoms on tomatoes. This would be blossom-end rot, caused by a calcium imbalance in the plant. Mulching will help even out moisture flow, and addition of calcium through foliar fertilizers may help, but control will be a challenge in a drought year.

[By JOHN FULTON, University of Illinois Extension]