Lawn problems difficult to diagnose

Q: For the last two seasons I have been plagued with a lawn fungus. What causes this fungus? How and when is the best time to try and control the disease? I water in the early morning and put down fungicide but I don't think I am doing it properly.

A: Disease problems on lawns are very hard to diagnose and require a professional . I can sometimes determine the differences between lawn diseases and insect problems or even irrigation problems, but even some of these get confusing.

Often times many of the problems are interrelated. For instance, if a lawn is not healthy or has been overfertilized, this can lead to disease or insect problems.

I do not feel comfortable recommending the treatment of a lawn problem with fungicides until it has been confirmed as a disease. I can sometimes determine lawn problems through digital pictures sent to me by e-mail. Most of the time it is elimination of other potential problems then narrowing it down to a disease problem.

When it gets to the disease level, it then depends on what disease it might be. Different fungicides treat different diseases. If you can get me three or four pictures of your lawn, we can work through this in a process of elimination.

Q: I love Texas ranger sage bushes and have several of them. Mine never seem to bloom as fully as others I see. I was told that only last year's branches will bloom this year, but mine get so big I have to trim them each winter. Am I trimming off the parts that would bloom? Others I see appear to have been recently trimmed but are in glorious color while mine only have a few blooms. Can you give me some advice?

A: You are almost answering your own question so let me help guide you. First of all, if you are using a hedge shears for pruning Texas rangers then this is your problem. This is absolutely the wrong way to prune this plant unless you are using it as a hedge.

You should never, ever use a hedge shears for pruning unless it is a hedge. All other shrubs, and in particular those that flower during the summer months, should never be hedge pruned. This removes only last year's, and perhaps the last two year's, worth of growth.

The older growth remains and just continues to get woodier and reduces flowering. The wood that has been pruned with a hedge shears becomes denser and restricts light into the canopy. Light is needed for new growth and flower production.

The proper way to prune summer-flowering shrubs is to use hand pruners, preferably a bypass pruner, which is one that operates more like a scissors when it cuts. Avoid using anvil-type pruners; these are pruners that have a blade that cuts on a solid piece of steel below it, which resembles an anvil .

Flowering shrubs should always be pruned immediately after they have finished flowering for the season. When pruning flowering shrubs, they are always pruned by making only two to five cuts toward the base of the plant. This removes entire stems containing several years of growth and opens the canopy for penetration by sunlight, renewed growth and improved flowering. You should aim for removing one third of the plant canopy every two to three years.

If the shrub is too large, you should try to reduce the size of the plant by removing the oldest wood at its base, which helps to renew the shrub, reduce its size and keep it more juvenile.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at morrisr@unce.unr.edu.