Saturday is Basil Day at the University of Nevada Cooperative Extension Master Gardener Orchard in North Las Vegas. The event, scheduled from 9 a.m. to noon, features 17 varieties of basil grown there.
Ryan Taliaferro, formerly an executive chef with the Ritz-Carlton, will demonstrate how to use basil in several unique recipes. Also, Diane Greene from Herbs by Diane in Boulder City will present how she grows basil here for the local chefs to maintain consistent quality. Food will be prepared for the demonstration so a $5 donation will be requested at the door.
Reservations are required. If you want more information, please contact me at firstname.lastname@example.org or call our master gardener help line at 257-5555.
Q: I live on the east side of the Las Vegas Valley and planted an African sumac in my front yard one year ago. It had been doing fine however I’ve recently noticed that its leaves all over the tree were shriveling quite noticeably. They are not falling off. Am I not giving it enough water?
A: See if the tree is in fact dead or just in some sort of shock. Sometimes shock due to temporary lack of water or drift from a weed killer can cause the leaves to die but not the tree.
To see if this is temporary and the tree has a good chance of recovering, simply bend the branches that have the dead leaves. If the branches are supple and do not snap off, then it might be temporary and you can just wait for new growth to appear. Continue to care for it normally.
Applying a fertilizer too close to the trunk also can kill the tree. All fertilizers are salts. This salt can kill young trees easily and quickly if irrigation water that has dissolved the salts in it comes in contact with the trunk. Keep fertilizers at least a foot or more from the trunk. Use fertilizer stakes. They are very convenient .
Since you are telling me it is “all over the tree” that usually pinpoints the problem to the roots or lower trunk area. Problems that can cause this sort of plant response can be planting it too deep, not staking the tree properly , not using enough soil amendment in the planting hole, planting in a hot location in the yard and using rock mulch, and damage to the trunk from lawn mowers or line trimmers, to name a few.
A fairly common problem is planting too deep. Pull the soil and mulch away from the tree trunk until you start to see the roots from the container . These roots should be no more than perhaps one-half inch below the soil surface .
If rock or wood mulch that can hold water are in contact with the trunk, then you might cause the trunk to “rot.” Take your thumb or fingernail and lightly scrape the surface that was below the soil or mulch. This should be green . If it is brown, then the tree has collar rot and is a goner. If it’s not brown, then remove the soil and mulch 6 inches away from the trunk.
The tree should have been staked solidly into the ground to prevent the rootball from moving once planted. It is easy to see if this is the problem because the tree will not be anchored solidly into the soil. Move the trunk, around chest height, a few inches in several directions. Watch the soil surface covering the roots. The rootball and soil covering it should not move at all. If this is the problem, it will usually cause poor, weak growth and not death.
Make sure the tree is being watered with enough water at one time. Figure a 5-gallon tree should receive about 10 gallons of water evenly distributed around the trunk at each watering. This would require two emitters at a minimum about a foot from the trunk. Three would be better.
Sumacs don’t seem to suffer from overwatering provided excess water can drain from the roots. When overwatered, sumacs usually grow like crazy with a lot of weak, succulent growth. Homeowners frequently think this is a sign they are doing well but it is really a sign of poor water management.
Q: I am sending you pictures of our red-tipped photinias from our backyard. We have 10 of these plants and two are in bad shape. The ones in particular are in the southwest part of the yard. They are getting plenty of water, just like the other plants. All of the leaves are brown (sunburned) but the plant is not dead. There is new growth on these plants. I say they were in the western-side sun too long, and with the hot temps here in Vegas, they met their match. My wife says that they are diseased. Who is right?
A: You are.
I have not seen a full-blown disease on photinia here in the Las Vegas Valley in 25 years. All of the problems with photinia have been water, soil and microclimate related. They do not like hot locations in the yard, in particular southern or western locations with radiated heat from walls.
They do not like rock mulch. The rock radiates too much heat back to the canopy. Over time, the rock mulch makes the soil even poorer than it already is. It doesn’t like our soil’s high pH (high alkalinity) and usually begins to yellow and scorch about five years after planting. Photinia seems to do fairly well in these bad locations for a few years and then begins to die back. If this is the case, it is not a true disease but caused by the environment.
If on the south and west sides, photinia would prefer to be away from hot walls. It prefers wood mulch, not rock mulch, and will do well if fertilized with fertilizer plus iron in the early spring of every year.
It should be watered as any other woody, nondesert plant in the yard, not daily but every few days and deeply (gallons) not with just a few minutes of water.
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 email@example.com.