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Monday, December 16, 2019

Controlling Springtails without Chemicals

Q. Each year around the end of February until the end of May I experience and irritating problem with springtails. Do you have and suggestions how to eliminate them? I don’t have decaying plants or problem with water in that area.

A. Springtails are tiny insects that jump in the air en masse when disturbed, usually at ground level. They love it wet. Springtails are sometimes confused with leafhoppers. But leafhoppers, also very small, reproduce and feed higher on plant leaves of plants like grapes and vegetables. Leafhoppers start appearing about April or May, the time when springtails are disappearing because of the heat and dryness. Both jump about the same distances when disturbed but look totally different with a hand lens or microscope.
            I can see you know this insect because springtails are found commonly in wet soils with rotting or decaying plants or infesting open bodies of water like summing pools and puddles. That would’ve been my first comment to you if you hadn’t made that last statement. Sometimes springtails become a nuisance inside the house in wet areas with light like bathrooms. Outside, I commonly see them in cooler, dark areas of lawns that are kept too wet during the cooler months. Springtails like stagnant, wet areas and are attracted to light. I’ve seen them as nuisance problems in swimming pools or spas. Leafhoppers, on the other hand, like it hot and dry.
            The bottom line in all habitats suitable for springtails is water or wetness. If it’s dry, they will disappear. They must feed and so rotting or decaying plants is important nearby, but water and wetness is more important. So, in our climate oftentimes they are found in irrigated shady spots.
            I know what you told me, but the key to managing or eliminating these guys is drying up wet areas. This might be as simple as improving air circulation in that area. Wetness is oftentimes accentuated in darker areas without much air movement or north sides of buildings.
            Pesticides do not work in the long haul. It’s really getting the area to dry up will or at least should clean up the problem. Ways to dry it out are to get more air movement in that area and/or more light. The rooting plants (organic matter they use for feed) will eventually disappear with time.

Be careful of excessive irrigation nearby. Do not water daily. Water and then let the surface area dry out.
Use deeper rooted plants in the area if plants are there. Bigger, deep rooted plants can handle longer periods of time without water applied.
If mulch is present, let it dry out before irrigating again or remove it. If rock is used, smaller rock like ¼ inch minus might allow you to keep the area drier and longer times between irrigations.

If it is unbearable then try spraying the area starting in late January with one of the horticultural oils. Spray the surface of the soil in hopes of suffocating them.
I would like you to read the information at this link

Figs Need Water to Produce Figs

Q. We're considering planting a fig tree grove in our school garden this year. How long typically does it take for them to produce figs ready for harvest?
12 year old fig tree kept small by pruning

A. Figs produce fruit very quickly after planting. You should start seeing fruit produced the year after planting in most varieties. Remember, figs produce fruit on the wood that grew last year as well as the wood actively growing.
            Figs can be very big trees if you allow them to grow. They can also be cut back to a much smaller size. You mentioned planting a grove of figs. Their planting distances apart should be the same as their maximum height. If you plant them 10 feet apart, don’t let them grow above 10 feet tall.

Figs with early Briba crop and later main crop growing together

            Remember that figs do great and desert climates, in desert soils, in the desert heat with low humidity. But they are heavy water users much like palm trees. Water them the same as you would any other fruit tree and don’t expect production if you don’t give them enough water. They will benefit from soil covered with woodchips simply because the woodchips keep the soil moist longer.

Two Different Types of Trees: Palo Verde and Crepe Myrtle

Q. I have a Museum Palo Verde and a crepe myrtle planted in the Fall of 2012. The  Palo Verde has grown well but the crepe myrtle hasn’t grown much in seven years. The roots of the Palo Verde are now lifting the stone ring I built around it. Can those big roots be cut out?

A. Palo Verde 

I will tell you about cutting the roots at the end but let’s talk about your situation first. You have two different types of trees; the Palo Verde is native to the desert Southwest and considered xeric (desert adapted) while the crepe myrtle is native to the wetter and richer soils of South and Southeast Asia. It is considered mesic and not desert adapted. You can’t grow them the same way, under the same conditions, and have good results.
            The Palo Verde can handle the poor growing conditions of our desert while the crepe myrtle must be pampered. Your crepe myrtle isn’t getting pampered that’s why you have problems with it. These two trees are planted, managed and irrigated differently.
            The Palo Verde will grow roots where water is applied to desert soils. If you water Palo Verde 2 to 3 feet deep and let the upper foot of soil dry between irrigations, the roots will  grow mostly 2 to 3 feet deep and not bother that stone ring lying on the surface of the soil. You can  control its rate of growth by giving it lots of water occasionally and let the soil dry out before the next irrigation. Every time it gets a deep drink of water, it will grow. When the soil is dry, it does not.
            The Palo Verde is more forgiving of desert soil even when it’s planted badly. I’m not saying it was or wasn’t planted correctly, but it tolerates bad soils better if they are amended before planting. The Palo Verde will look better if it’s planted in decent soil at the beginning, but how and where you apply water will dictate how fast it grows and where its roots are located.
            You can’t do any of those things with crepe myrtle. Crepe myrtle will not tolerate soils if amended badly at planting time. It won’t like the hotter and harsher locations in the landscape. But Palo Verde will. Crepe myrtle will grow much better if the soil is continuously moist and covered with 3 to 4 inches of woodchips. Palo Verde will like this too, but it can sail through desert hotspots and poorly amended soils better than crepe myrtle.
            If they are both on the same irrigation valve, then you will have a problem because the Palo Verde will get water when you think the crepe myrtle needs it. They should be watered separately. That would be too often for Palo Verde. It will grow shallow roots because its watered too often. If these trees are on separate irrigation valves, then the Palo Verde can be watered less often than the crepe myrtle. Using separate valves benefits both of them.
            Can you cut off the roots of the Palo Verde that are causing problems? You can remove a few of them each year for the next three years but start watering the Palo Verde less often and give it more water with each of its applications. Get its roots deeper and out of the way. Apply water to at least half the area under the canopies of these trees.

Crepe Myrtle

Readers crepe myrtle

On your crepe myrtle, I would put a ½ to one inch layer of compost 12 inches away from the trunk to about three foot away. You can get it bagged from Viragrow. I think you will need about ten bags or less. Concentrate the compost closest to irrigation water or drip emitters where it will get wet and decompose faster and move the leachate into the ground toward the roots. The tree will respond faster if you can auger as many holes as possible around the trunk to about 12 inches deep and fill them with compost. Spreading it on the top of the soil will work but it will take longer for the tree to get the benefits.

Cover that compost area with woodchips about three to four inches deep. You can get them free from the University Orchard in NLV (N. Decatur and Horse Drive) or their office complex on the corner of Paradise Rd and Windmill just south of the airport. Call their Master Gardener helpline at 702-257-5555 and make sure they have the woodchips available before you go.

Then I would prune back the height of your crepe myrtle and try to force some new growth lower on the trunk. Prune the top back as much as possible while still keeping the growth on top. I am hoping you will see some new growth lower on the trunk in the spring. This growth will help strengthen the trunk and I am hoping you will not need to stake it in a couple of years.

Plants to Replace Roses for Low Light Levels

Q. My roses are not doing good because there is no sun by the wall where they are planted. Can you please suggest other flowers that can be planted there?

From the look of the leaves in this picture you might need to amend the soil before planting roses. Roses appreciate amended soil in the soil surface covered in wood chips, not rock.

A. Whenever you have a location in a landscape that’s not getting much sun, you can’t grow flowering plants in that location. They need more sun  to produce flowers. Instead, focus on plants that do not produce flowers but are still ornamental. In other words, forget most flowering plants in that location. Flowering plants will need at least six to eight hours of sunlight to flower well.
            Some examples of ornamental, nonflowering plants for nondesert shady areas might include Agapanthus, Box Leaf Euonymus, Dwarf Indian Hawthorne, asparagus fern, Mondo grass, sago palm, Algerian ivy, purple flax, split leaf philodendron, dwarf Burford Holly, heavenly bamboo, and Oregon grape. All of these require compost mixed into the soil at the time of planting, moist soil and they will do better with woodchip mulch on the soil surface.

All of these plants are mesic (nondesert) so make sure the soil is amended with compost at the time of planting.