Landscapers using mulching mower should cut back on fertilizer


Q: The landscapers for our HOA are using mulching mowers on our grass. The cut grass often remains on top, browns and causes the grass under to brown out also. Should grass be mulched in our desert? The landscape foremen bagged the grass and took it away.

A: Mulching mowers work good as long as not too much nitrogen fertilizer is applied, the mower blades are kept sharp, the mower is not operated at a speed that is too fast, and the mower is a true mulching mower and not a conventional mower modified with mulching blades.

True mulching mowers have a deck designed to provide a longer lift time after the grass blades are cut. A longer lift time allows the leaf blades more time to be cut or mulched properly. This extra time, combined with a sharp blade and a correct mowing speed, results in finely mulched turfgrass clippings.

This time of year fescue grass loves cool weather and grows very rapidly. If too much nitrogen is applied during cool weather, excessive growth results. Weekly mowing with a mulching mower cannot keep up with this rapid growth.

Either the lawn has to be mowed more often or less fertilizer should be applied.

Your landscapers need to cut back on fertilizer applications during cool weather and use about half the rate listed on the bag. Mulched grass clippings return a lot of fertilizer back to the lawn.

They also need to mow slower and not try to rush through a landscape. This allows the mulching blade to cut the blades more often and the mulched clippings will fall between the grass blades and never seen on the surface.

If they don’t balance mowing their applications of fertilizers then they will need to pick up the clippings if they want to leave a landscape that you can walk through without tracking cut grass into residences.

One of the major reasons for introducing mulching mowers was to reduce the green waste entering our landfills.

Q: I have an oleander that suffered extensive freeze damage this past winter. It is still brown but coming back slowly. I would like to improve the looks of the bush without killing it. Should I prune the dead looking branches or just let it go?

A: Prune the oleander back to about an inch or two of the soil surface. After this, apply fertilizer and water it deeply several times a week apart.

If it has been established for at least a couple of years it will grow back with a lot of vigor. Oleanders are very drought tolerant but to look nice they require quite a bit of water.

Q: We have thousands of these beetles in our trees here in Henderson. Yesterday they collected on a neighbor’s car by the thousands. They sprayed them off. These bugs left imprints on the finish of their car that were unremovable. What are these bugs and what do we tell our pest control companies to do?

A: These are a type of stinkbug. I am not an expert on stinkbugs, but it is one of several types that can be found here. Most stinkbugs cause damage to plants or become a nuisance as yours have done.

Stinkbugs come in green and brown colors and in many different forms. Familiar relatives to stinkbugs are the squash bug and leaffooted plant bug, both very bad pests in squash and melons as well as pomegranates, pistachios and almonds.

There are a few stinkbugs that are good guys but not very many. In your case I think these are a nuisance but check your garden and landscape and see if they are feeding on important plants around your home.

Soap and water sprays applied directly to them at dusk is a good control measure that is relatively nontoxic to other insects as long as it is directed at the stinkbugs. You can buy Safers insecticidal soap at any nursery or garden center and it will be safe for plants listed on the label. Commercial insecticidal soaps are safer to use on plants than making your own from dishwashing liquid.

There are more toxic insecticides you can use as long as you don’t spray your fruits or vegetables with them. Be sure to read the labels of pesticides before buying and applying.

Q: I have trouble with my ocotillo. They get beautiful green leaves that last about two to three weeks and then turn brown and fall off. They are on my watering system. Are they getting too much water?

A: Ocotillo is a desert plant so it has special characteristics that allow it to survive when water is not available.

The first response ocotillo displays to a lack of water is to drop its leaves. Another reason it may drop its leaves is from the soil around its roots staying too wet. That makes diagnosis of leaf drop difficult.

If ocotillo is put on a “normal” irrigation schedule used for most home landscape plants, it would most likely receive water too often. It would, ideally, be irrigated with agave and yucca in a landscape, not photinia and star jasmine for instance.

It can tolerate frequent watering only if water drains from the soil quickly. If water in the soil drains easily then it might be able to handle the same irrigation frequency as photinia and star jasmine even though it would not be ideal for it.

It can probably handle an irrigation frequency of about once every two to three weeks in the summer but not more often than once a week.

In winter change it to once every four to six weeks. Use enough water to wet the soil at its base to a depth of about 18 inches. Three or four emitters spaced about 18 inches from an established plant would be adequate in most soils.

If you choose to water with a hose, filling a basin around the plant would make it easier to water. Watch for leaf discoloration or leaf drop to signal a time to rewater. Eventually this will help you anticipate a watering schedule for the plant.

Q: I have had Tecoma stans, yellow bells, in the backyard as well as lantana for the past three or four summers. They do well but never winter over. When I dig them up to replant, the root structures seem to be healthy and alive. The tag on the plant says they are cold-hardy. Is there anything I can do to help them winter over?

A: Are you thinking they are dead because the tops die back? It is seldom that I see these plants totally die out in the winter here. They do frequently die back to within a few inches of the soil surface during the winter.

They then can be cut back to about 1 inch from the ground in February and they come back like gangbusters in early spring with some water and fertilizer.

If they are dead, I am wondering if they are not getting enough water during the winter months to keep the roots from dying out. Normally a watering schedule of about every 10 days or so would be enough during the winter to keep them alive.

Otherwise try mulching over the tops of the plants with a few inches of wood mulch to keep the winter cold from damaging the roots. It is very rare these would die out in the winter here under normal landscape situations.

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.

 

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