Season ripe for thinning fruit trees

For those of you who still have lawns, now is a great time to aerate them and help get the roots as deep as possible before it gets hot. In addition to aeration, try mowing your lawn as high as you can.

Grass mowed higher has a deeper root system than grass that is mowed short. Mowing high helps roots grow deep, which in turn promotes better tolerance to drought. After aeration, it is also a good practice to apply a lawn fertilizer that has phosphorus in it to help stimulate root growth.

You should be thinning your fruit trees right about now. Thinning is removing some fruit from the trees so that the remaining fruit can get larger. I try to space apricots 2-4 inches apart while peaches and nectarines may be 4-6 inches apart. Apples and pears are thinned so that only one piece of fruit remains in each cluster. Try to thin when the fruit is about the size of your thumbnail. If you wait too long, you will not get any benefit from the thinning.

If some of your fruit trees or landscape plants are showing signs of yellowing, trying spraying them with a liquid iron fertilizer several times during the next six weeks. For many plants, one application is not enough.

Mix a small amount of liquid dishwashing detergent, about 1 teaspoon per gallon, with the liquid iron fertilizer before spraying it on the leaves. It is best to avoid using tap water when mixing iron fertilizer sprays. Try using distilled or reverse osmosis water instead. I usually like to put a small amount of general purpose liquid fertilizer in the sprayer as well.

As it is getting hotter outside, spray liquid fertilizers on plant foliage only during the cool mornings or evenings.

Q: Last fall I planted snapdragons. After the first phase finished blooming, I cut off the spent stalks. The second set of stalks bloomed with gusto. Now they are almost finished. If I cut these back, will a third set of stalks materialize and bloom or is this the finish of a life cycle for my plants? Will the summer heat completely annihilate them? Maybe I should start over now with new plants.

A: It is always wise to remove flowers when they are finished blooming.

For many flowers, the next step after blooming is setting seeds. Forming seeds requires energy that could be used by the plant for other things such as new growth or improved rooting. Removing spent flowers, also called dead heading, preserves energy that would normally be used by the plant to produce seeds.

Snapdragons are cool-season bedding plants. They prefer cooler months and the cold rather than our summer heat. These snapdragons may try to send up another set of flowers, but time is not on their side. If the weather stays cool, you may get another flush of flowers, but I doubt it. Summer is coming and so is the end of our snapdragon season.

When working with bedding plants, we usually pull out the cool-season plants in early spring and replant the area with warm-season plants. This is usually during their peak bloom. Hot- or warm-weather bedding plants usually are planted around the middle to the end of March.

Q: We had many Red Delicious apples last year but once they ripened to a certain point the birds helped themselves for the remainder of the season. Is there anything I can do? When I drive through the orange groves on Interstate 5 in California I notice shiny tinsel reflecting in the trees. Is that a deterrent for birds?

A: At the University of Nevada Cooperative Extension Master Gardener Orchard in North Las Vegas we have tried hanging tinsel in the trees, hanging CDs and DVDs, a scarecrow, fake owls, bird-scaring devices that make loud noises, devices that make noises like threatened or injured birds, noises like hawks and fishing line hanging from supports over the trees, and none of them work for very long.

If you use any scare tactic at all, you have to put this device in the trees just a bit before the fruit ripens and keep it on during harvest. When harvest is over, you must take it down and wait until next season to put it up again. If you leave any devices in the trees too long, the birds get used to them.

Q: I picked some brown pods from a lilac tree. There seems to be a red seed inside. Can I plant the seed or the pod?

A: I think you are asking me if you can start lilacs from seed and whether it is worth it or not. It is not an easy task so unless you are a dedicated gardener, I would not recommend it.

Lilac seeds need to be placed under temperatures similar to the refrigerator and kept from dehydrating for about two months before they are ready to germinate. It will probably take somewhere between three and four years before you’ll get any blooms from a plant started from a seed.

Q: I live in Sandy Valley and have a question concerning our Southern live oak. The tree was planted in March 2007. The leaves stayed green all winter long and it looked healthy. Now, although we are getting new green leaves on every branch, the larger leaves are turning yellow and even some of the newer ones are yellowing. We fertilized it three weeks ago and are watering it with plenty of water three times a week.

A: Evergreen trees like the Southern live oak drop their leaves in the spring and it is not uncommon for them to have a leaf drop this time of year. Stay focused on the new growth. If it is healthy and growing vigorously, I would not worry.

I am assuming that since this is Sandy Valley, the soil is relatively sandy and drains easily. Even though they are evergreen, if it gets too cold, the trees will drop their leaves.

Make sure you did not put the fertilizer too close to the trunk and that the drip emitters are watering the fertilizer into the roots. Secondly, the drip emitters should be inside of the planting hole, not outside of it. If the emitters are outside of the planting hole, it is possible that the water may run straight through the soil and never get the root ball wet. This can cause leaf drop.

It’s really a good idea to water with a hose even though you have drip emitters on the tree, especially during the first month after planting and good growing weather.

The soil around the root ball should stay moist but not become overly wet. It is difficult for me to tell you how often to apply the water since I don’t know how your soil is holding water. Basically, you want to flood the whole area around the root ball every time you water. Three times a week in sandy soil does not sound excessive to me.

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 extremehort@aol.com.