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Sunday, June 12, 2016

Water Every Day and Still Not Enough

Q. I put four African sumac trees in our backyard last September. I am watering them now every Tuesday, Thursday and Saturday for 20 minutes. About two weeks ago the leaves turned brown and fell off. If this continues will the tree lose all its leaves?

A. You can be watering newly planted trees and they can be suffering from drought at the same time.
Container and boxed trees are grown in soils that are totally different from the soils in the landscape. Container soils are looser and lighter than landscape soils.
When these trees are planted, the soil is pushed in around the root ball and, if you are lucky, the plants are watered in twice with a hose. A basin is placed around the trees so they can be given additional water until they are established.
Irrigation emitters are sometimes placed too far from the trunk and the water from the emitters wets the landscape soil but it does not move into the root ball because the soils are totally different from each other.
How to correct this? Always, always, always water newly planted trees and shrubs with water from a hose directed on top of the soil and at the base of the tree. Never, never, never rely on an irrigation system by itself to deliver the water where it is needed after an installation.
Hand water with a hose twice a week. Supplement the water from the hose with your irrigation system on the same days you water by hand. Select your irrigation days and give the plants a rest (no applied water) for one or two days between irrigations.


Why Apricots and Early Peaches Were Bland This Spring

Our spring this year was cool and wet. Even our early summer was that way. This kind of weather was good for producing a lot of tomatoes but not necessarily for high-quality tree fruits.

Early apricots and even some peaches can be harvested in mid to late May in our climate. The best early-season fruit bright, sunny skies and warm temperatures. This year our skies were overcast and temperatures were cool all the way into May.
Earlitreat peach, one of the earliest peaches, can be harvested in mid-May in the Las Vegas area. This is even before most apricots are ready. On a five star scale, this is a four-star peach.
Temperatures below 95° F are great for setting tomato fruit but not necessarily the best when it comes to producing high quality tree fruit. The taste of fruits is complex. It isn't just about sugar content. Devices like refractometer
Refractometers measure total soluble solids which is a "reflection" of sugar content. But sugar content may not tell you anything about quality.
s only measure total soluble solids which can be equated with sugar content. Sugars only provide sweetness.

We need other tastes to provide a good flavor profile to fruit. Flavor begins with a balance between sugars and acids that we find favorable.This includes a mixture of organic acids such as acetic, tartaric and malic acids to balance flavor and aromatic volatiles that provide that first whiff of the fruit even before it enters our mouth.
This is Indian blood peach which has a wonderful floral taste and aroma when grown in our desert climate and allowed to tree ripene. It has been around for a long time and is implanted much anymore.Most people pick it too soon and you do not get all of those floral notes.
Cool temperatures and cloudy skies do not promote good sugar development. Under these conditions sugar content stays lower than normal and the acid content remains high. So the ratio of acids to sugars is not the best. When we have bright, sunny skies and warm to high temperatures then sugar content is boosted and the ratio of sugar to acids becomes delicious.

The only other thing we need to make this a perfect fruit is to allow it to mature so that those volatiles fill our noses. This is why when I shop for fruit I use my nose before I buy it. You can smell good fruit before you taste it. Ask any fruit loving bird.

Prevent Plant Sunburn with Adequate Water and Wood Mulch

Some thin barked trees and shrubs will get sunburned if they don't have enough protection from strong sunlight.
This reddish-brown discoloration is sunburn. In the first stage of sunburn we see the beginning of death onsides exposed to the South and West
Plants that typically get sunburn include many of our fruit trees, mostly peach and apples. Ornamental trees and shrubs also get sunburn. I get a lot of pictures of sunburn sent to me with sunburn and include Japanese blueberry, locust trees, ash trees, Indian Hawthorn, and others. 


This is the trunk of an ash tree on its west side. It first got sunburn. After sunburn the borers attacked it. What you see now is loose bark covering dead wood killed by borers. You can take your fingers and just pull this bark off of the trunk easily. You should do it anyway. You will not hurt anything. That site is already dead. The tree is still alive because the trunk is alive on the other side of the tree.
The natural way to protect these plants from sunburn is to allow these plants to shade their own trunks and stems with leaves. Not providing enough water can thin out the canopy of trees and shrubs and encourages sunburn. 

When you pull this bark away from the trunk you will see oval-shaped holes in the wood. These are exit holes of the bores. Removing the bark also removes hiding places and birds have a better chance picking them off when they emerge.

Having rock mulch around plants that do not like rock mulch also reduces the number of leaves and increases the chance of sunburn. Plants that do not like rock mulch, like the ones I mentioned above, will develop an open canopy, leaf loss, and sunburn. 
This is sunburn on a bottle tree. The leaves drop from the canopy and expose the trunk and limbs. High sunlight intensity causes sunburn once the leaves are gone
What's the problem with sunburn? When we get sunburn we recover. When plants get sunburn, particularly in a desert climate, they frequently decline and die. Attack by boring insects, or borers, is the first phase after sunburn. The borers create more damage and more leaf loss and more sunburn. After that, the plant falls into a death spiral. 
Sunburn caused the top of this Japanese blueberry to die. Then the top had to be removed and it was pretty ugly. Japanese blueberry should not be in rock mulch. They should have wood chips around them.
Use surface mulches particularly wood chips and not bark. Don't water trees and shrubs daily but water them two or three times each week during the heat of the summer. Reduce the number of times per week during the cooler months. When you do water, give them adequate amounts so that the soil is wet to at least 12 inches and preferably 18 inches.

Master Gardener 2016 Fall Graduates


Do you love gardening and want to share your experiences?

It’s time to register for the FALL 2016 Master Gardener Training class in Las Vegas!

The Master Gardeners of Southern Nevada will hold registration on Wednesday, June 22 at 9 a.m. We will give you an overview of the training and program requirements, and offer you the opportunity to fill out an application and have an interview with a current Master Gardener.  Students will be notified of their acceptance by June 30. Payment of class fees ($200) will be due by July 8.

Our mission is to train community volunteers in appropriate desert gardening practices. Eighty hours of class training and 50 hours of volunteer work on approved projects are required in order to become a Master Gardener. Classes are scheduled on most MWF from 8:30 – 12:30 from September 9 through October 26 (based on instructor availability). You must attend all 20 classes. Classes are held at Cooperative Extension, 8050 Paradise Road, LV 89123 (Windmill exit off the 215)

You do not need a gardening background in order to become a Master Gardener! The most important qualifications are commitments to complete the Training and to share your knowledge through Volunteer service.

Contact Lori Leas at leasl@unce.unr.edu to reserve a space. Please indicate the registration date of your choice. Full details will be emailed to all who pre-register. 

Pine Trees Need More Water in the Summer

Q. How often and how many minutes of water should I give my pine tree?

A. Regarding your pine tree, it will do best if you can give the tree lots of water all at once very slowly and then hold off on your watering.To do this, it is sometimes best to construct a basin around the trunk 2 to 3 feet wide to hold the water.
When I pine tree looks sparse and not fall it is usually because of a lack of water. Add water to the base of the pine tree with a hose once a week during hot weather or add more drip emitters
Because of how irrigation systems are designed, sometimes you can reschedule your irrigation clock and sometimes you cannot because it's tied to other plants and their watering schedules. If you can hold off your watering to twice a week it would be better for the plant.

As far as the number of minutes goes, I don't know. Trees drink gallons of water, they don't drink in minutes. If you feel like the trees are not getting enough water then I would not increase the number of minutes. I would increase the number of drip emitters or, if you are not using drip emitters, increase the number of places that deliver water so that the tree receives more water during each irrigation.

Browning on Apple Tree Is Drought

Q. see (photo) my apple tree it is not in good condition, why? Can you tell me what I can do to help my tree? 


A. Thanks for the picture it helped. That is leaf scorch and leaf scorch is caused by not enough water making it from the roots to the leaves during hot dry weather usually. A lack of water getting to the leaves can be caused by soil problems such as too much salt in the soil, a lack of water in the soil, root damage, damage to the trunk so it transports less water or damage to limbs which does the same thing. 

When leaf scorch appears all through the tree canopy then we can pinpoint the trunk, roots or soil. In your particular case I think it is just a lack of water around the roots. The tree appears healthy otherwise. Take a hose and soak the area under the tree canopy with about 30 gallons of water. Repeat this again twice during the week. 

The leaves which are already damaged will not recover. But any new leaves produced after you begin this new irrigation should come out without scorching. 

If this is the case, you need to add more drip emitters around the tree or increase the number of minutes you water. Increasing the number of drip emitters is a better solution if everything else is getting the right amount of water.


Geranium and Petunia Damage on the Rise

Q. I had a beautiful  Geranium plant with lots of flowers in a large pot that has a dripper. Now that the blooms have died all the leaves are turning brown and  have holes in them. What went wrong? If I cut the plant back, will it bloom again.

A. Two things come to mind without looking at the plant, the soil or container. First of all, geraniums are cool weather plants and don't like the heat. If they are going to survive during the heat they need to have an Eastern or northern exposure which is protected from late afternoon sun. They do best in bright locations that have filtered shade. 

Secondly, this is the time of year we start to see flowers eliminated by tobacco budworm. Holes in the leaves are dead giveaway for tobacco budworm. Read more about it here.


It is possible to cut them back, fertilize and water them and get them to regrow but you should spray for the tobacco budworm to protect the new blossoms. If you have petunias, they can attack them as well.