Be on lookout for flea beetles, hornworms
Two new insect pests popped up in the last couple of weeks. One is the grape flea beetle, which chews holes in grape leaves, and the tomato hornworm, which can be spotted on anything that is soft and succulent. They will eat new growth on grapes, tomatoes, herbs and the like. The culprit that lays eggs that develop into the hornworm is the sphinx moth. Organic sprays of Dipel or any spray containing Bt will work.
If you are getting my free fruit newsletter, you can read all about it. I produce two newsletters: a weekly gardening newsletter and a fruit newsletter, each requiring a separate enrollment. If you are not getting the fruit newsletter, please e-mail me at morrisr@unce.unr.edu. For those of you without an e-mail address, a hard copy can be mailed to you by phoning 257-5509.
We will now go to watering twice a week, on Saturdays and Wednesdays, at the University of Nevada Cooperative Extension Master Gardeners Orchard in North Las Vegas. As it gets hotter, the plants require more water.
Q: I have a few vines that climb the wall and I don’t remember their names. They did very well the past few summers and through this winter. This spring they have thinned out and appear to be dying. I fertilized all my plants and trees with an all-purpose plant food approximately a month ago. The vines are getting sufficient water. What could be the problem?
A: Without knowing the vines it is a potshot. If the vines are cold sensitive, then it could be winter damage. There may not be sufficient enough cold to completely kill them but enough to damage them. This could cause them to come out weak the following spring, but they usually recover later in the season.
It could be that the vines were planted in the wrong microclimate in the landscape. If these were vines that are heat sensitive or sensitive to desert soils, then they could be declining just due to improper placement in the microclimate or improper soil preparation at the time of planting. If they are sensitive to our desert soils and surrounded by rock mulch, they could do OK for a few years and then decline in three to five years.
I would suggest you try to get the vines identified and make sure they are in the correct exposure or microclimate. Plants sensitive to heat and drought usually have to be planted on the east side of the landscape or get some filtered sun during the day and protection from late afternoon sun.
Regardless, if the plants were not planted in soils modified with compost, they will not perform very well. Our soils are horrible. Secondly, many plants here will perform better with an organic surface mulch rather than rock mulch. See if you can get a sample to the master gardeners at our office for identification. They can be reached at 257-5555.
Q: I read your recent article on fruit pruning, but there was nothing about pomegranates. Please provide some information.
A: Generally pomegranates are not pruned after establishing their basic structure except for removing crossed limbs, broken branches and suckers or watersprouts (vertical growth). Basic structures are as a bush form or multitrunked tree.
Q: I am having a problem with clover taking over my lawn and I am seeking your assistance. I have tried Scotts Turf Builder with weed control and it is not fixing it. Do you have any other suggestions that will get rid of the clover yet not harm my grass?
A: Invasion of clover into a lawn is usually a sign that the lawn is beginning to weaken due to a lack of nitrogen fertilizer, an excess of phosphorus fertilizer or both. Lawns primarily need high-nitrogen fertilizers unless they are being established. High-phosphorus fertilizers are necessary during the establishment phase when lawn grasses are setting down roots.
Once the grass roots have been established, phosphorus fertilizers should be applied in small amounts. Typically a good turfgrass fertilizer is one that has three to four times the amount of nitrogen than it does phosphorus.
For instance, a fertilizer that has 20 percent nitrogen should contain no more than 7 percent phosphorus. These are represented by the first two numbers on the bag. The third number on the fertilizer bag is potassium. Applying excess potassium is not as critical as applying excess phosphorus. Potassium content in a fertilizer can be half of the nitrogen or higher. So an ideal turfgrass fertilizer would have a ratio of nitrogen to phosphorus to potassium of around 20-7-14.
Once established, clover can be difficult to eradicate. There are herbicides that are particularly effective in controlling clover. They can be applied as a liquid spray to the lawn or as a dry product. These products will list clover on their labels.
Timing and proper application is important for good control. You will have better control applying these products in the cool fall months than you will during the hot summer months.
While you’re waiting for fall, thicken up your lawn by applying a fertilizer like I described above at regular intervals as prescribed on the fertilizer bag. These will vary depending on the type of fertilizer and how much slow release nitrogen it contains. This fall, some time from mid-September to mid-October, apply the clover-control chemicals.
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.