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Bob Morris

Bob Morris

Bob Morris is a horticulture expert living in Las Vegas and professor emeritus for the University of Nevada. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.

Watering cactus too often can lead to plant death

Be careful when putting cactuses on an automatic water or irrigation timer. They are watered so infrequently that it sometimes makes sense to water these plants manually with a hose rather than automating the task.

No simple way to prevent tree suckers

Some plants grow suckers at the base of the plant and others produce suckers, or new growth, a distance away from the plant. So far, the only practical way to eliminate them is to slice the roots and remove these plants, roots and all.

Italian cypress grows too tall to be used in residential landscapes

Q: I have just about reached my maximum frustration level with my 35 Italian cypresses. Between spraying them down weekly in the summer to keep the mites off and them not standing on their own without staking and guy wires for 2½ years, I am ready to give up. I am thinking about replacing them with 5-gallon dwarf golden arborvitae because they are smaller and easier to spray.

Agave weevils damaging cactuses this time of year

Cactuses, particularly agaves, are rotting and dying from damage by the agave weevil, which that lays its eggs at the base of agave leaves. As their young hatch from the eggs, they burrow into the stem of the agave and all through it, including the roots.

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Leaf odor can differentiate bay laurel, Carolina cherry laurel

One easy way to tell the difference between a bay laurel and a Carolina cherry laurel is to crush the leaves and smell the herbal aroma. Bay laurel leaves have a pungent aroma. When you crush the leaves of Carolina cherry laurel, they have an aroma of maraschino cherries rather than herbal.

Standard-sized apple tree cannot be pruned to dwarf size

Standard-sized apple trees may grow to 35 or 40 feet in height. You might be able to keep a standard-sized tree under 20 feet tall through pruning, but the standard-sized apple tree is just too vigorous for pruning to short heights.

Rainy conditions can cause diseases in plants

A disease called fire blight might pop up in some pear and apple trees beginning around May. It can be common several weeks after spring rains, particularly if trees were flowering. It can lead to tree death if not controlled when it’s first seen.

Delay grape pruning as long as possible

Delay pruning grapes as long as possible in the spring to reduce disease possibilities and avoid any late spring frost damage after pruning. Immediately after pruning grapes, consider applying a fungicide to the vines if there were problems with grape bunch diseases last year.

Mexican petunia needs to be contained to area

My experience with Mexican petunia is that it grows like a weed, and I consider it the broadleaf version of Bermuda grass, aka devil grass. If it’s contained in an area and prevented from spreading into the landscape, I think it will be OK.

Check for borers after rainfall

An infrequent desert rain is not a problem. But when irrigation water is applied over and over to a soil that is normally dry, these soils shift, collapse and chemically change. In urban landscapes, this can be potentially destructive.