Q. How often should I water my trees and shrubs with all this heat. The weather got hot so quickly, I’m not sure when to water. I have a California Pepper Tree, two big palm trees and five Japanese boxwood shrubs. California pepper tree that was planted too close to cement and so lifted it with its roots. A. First off, don’t violate your water purveyors watering directions. These policies are in place to coordinate community water use and lower the costs of supplying water to end users like you. If you live in Las Vegas you can see it here.             All the plants you mentioned are called “mesic” plants and require more frequent irrigation compared to (xeric) desert plants. The amount of applied water depends on the size of the plant. As plants get larger, more water is applied to a larger area (even though the water wets the same depth of soil) under the plants canopy. Watering cacti too often can contribute to fast growth and so much succulence it cant stand up against its own weight.             Apply water to all the area under the plants canopy. This advice might be difficult to do with larger trees like your California Pepper, so apply water to at least half the area under a plants canopy when they are big. This way they won’t blow over as easily during a windstorm. Watering frequently near the base of a plant can cause it to lose support during a windstorm.             Lawns, annual flowerbeds and raised beds for annual vegetables require daily, or near daily, applications of water. Sometimes they need water twice a day. These plants should receive water that wets the soil to a depth of about six to 10 inches with each watering. A piece of rebar can be used to judge how many minutes to water. Rebar pushes easily into wet soil.             Shrubs and patio trees should be watered to a depth of 18 inches. Medium sized trees around 30 feet tall should receive enough water to wet the soil to a depth of 24 inches. Large trees need the soil wet to a depth of 36 inches after an irrigation.             How to know if the applied water went deep enough? Use a straight, 4-foot-long steel rebar and push it into the soil after an irrigation. It stops going deeper where the water stops.             How to water deeper with the same number of minutes? Add more drip emitters under the plant.

Q. I recently harvested my garlic crop, wrapped it in burlap, and hung it up to dry.  How long should I let it dry in the Vegas heat? Last year I let it go for over a month and the bulbs got mushy. Freshly harvested garlic. A. If the bulbs got mushy then it was harvested too early or the bulbs stayed too wet. In our climate, don’t wrap garlic in burlap but dry it in the shade instead. I never had problems drying garlic. I leave the tops attached, bunch them together and hang them in the shade. Chesnok Red garlic hanging in the shade to finish drying.             To me, this seems a bit early to harvest garlic. My garlic was harvested in late May or June when the tops had dried back about 1/3 in the field. It is hard to tell without seeing them, but the bulbs should be fully developed when harvesting. Browning of the tops is a way to know if they are starting to mature or not. If you let the tops all turn brown then the “paper” wrapping around the bulbs will get damaged. Polish White garlic growing in North Las Vegas.             Garlic is planted in the Fall and harvested in early to mid-summer after the bulbs have formed. Shake the soil from the plants when you harvest, don’t wash them. I grew about 25 varieties of garlic and they all did well here. This is a good climate for garlic. So, keep an eye on the plants and harvest them when they are fully formed on their own and dry them in the shade.

Q. I have a 2-year old Flavor Supreme pluot and a four-year old Flavor King pluot. Recently my Santa Rosa plum (their pollinator) died from borers. The Flavor Supreme had only a few fruit while the Flavor King was loaded. Do I need to plant a plum tree to pollinate the Flavor Supreme? Or does it have a small number of fruit because it is only 2 years old?  Ripe Santa Rosa plum ready for picking. A. Flavor Supreme pluot has wonderful fruit but its production is sketchy because of spring freezes. So most likely the tree was thinned of some fruit by some late spring freezes. Plus, its only two years old! Some years Flavor Supreme may get no fruit even though it flowers because of a freeze. This is less likely to happen with Flavor King. Flavor King pluot. Has a lot of plum in its genetics.             Santa Rosa plum produces good soft fruit in our climate and is a good pollinator for most pluots. Flavor Supreme is a pollinator for Flavor King pluot as well. Throw Dapple Dandy pluot in that group as well. But pluots will still produce fruit without a Santa Rosa plum or pluot in your yard. Just possibly a lighter crop. If a neighbor has a Santa Rosa plum or Dapple Dandy pluot then it is to your benefit. Flavor Supreme pluot

            I am getting quite a few emails about cacti dying, particularly agave. Some are guessing the culprits are ants, diseases and other readers appear to be stumped. American Agave can die in about May of any year. Agave Weevil             The culprit is the agave weevil that lays its eggs at the base of agave leaves. As their young-uns hatch from the eggs, they burrow into the stem of the agave and all through it including the roots. The plant rots and dies from all the damage done usually in late April or May. We are seeing it now. A pesticide applied around its base in March, and lightly watered in, usually prevents the damage from getting worse. The other option is not to grow agave. Agave weevils can decimate agaves in May if left unchecked Drainage a Must             If you’ve never grown any cacti before, make sure the soil drains easily of water and that don’t water these plants too often. I have found a deep watering every three weeks is frequent enough to push new growth and get the plants larger. Know the Origin of Your Cactus  Some cacti are not meant for very hot locations because they come from milder climates. Photo taken at the LV Sorings Preserve. Some beautiful cacti and other succulents come from the hot, dry deserts of Central and North America. Make sure they are placed in full sun. Other cacti may come from milder, coastal or high-altitude desert climates and need protection from the intense Mojave Desert sun. Knowing where cacti come from empowers you and its landscape placement.

Q. I have a Mexican Bird of Paradise and ‘Sun Trumpet’ Tacoma plant growing close together. Both have deformed, dwarfed growth, and damaged leaves. The Bird of Paradise feels sticky as well. I tried sprays for insects, including Neem oil, and cut the plants down completely to have them grow back with the same issue. Other plants in the yard are doing fine. Any help is appreciated. Herbicides applied to the soil or on a hot windy day can result in damage to the leaves and stems of plants. Sometimes plant death. A. I don’t think these plants are facing a disease or insect problem.  Soil Contamination Possibly It is hard to say without guessing, but from your description it sounds like a soil contamination issue. Plant an ornamental grass and broadleaf plant in that area and see if you get the same response. If it were a cooler time of the year, I would tell you to germinate a seed mix with grasses and wildflowers in it. Brush Killer or Soil Sterilant             There may be a weed killer applied to this area and responsible for this problem. Some weed killers like dicamba, if applied at a heavy dose or used as a “brush killer”, can damage broadleaf plants like your Bird of Paradise and Tacoma and not hurt grasses. The high rate of this type of herbicide is why some weed killers are labeled as a “Brush Killer”. There are other weed killers sold as “Soil Sterilant” that can persist for years and kill most plants grown in that soil. Replace Soil or Change Plants             Some weed killers are difficult to remove by leaching with water. If the ornamental grass isn’t damaged but the broadleaf plants are, then either replace the soil in that area to a depth of about 12 inches deep or only grow ornamental grasses in that spot.

Q. I applied Bonide Tree and Shrub insect control for borers and miners about six weeks ago. Now my plants are growing weird and possibly dying. Once I saw this problem, I sprayed for diseases and then today for insects. What is going on? Picture not available A. The damage to the plant was probably weed killer (herbicide) damage judging from the distorted leaves and dieback. There is not much to do at this point except spray the foliage with water, irrigate, and make sure the plants were fertilized in the spring, so they are in their best health to recover as quickly as possible. Then wait and see what happens. There is no magic cure at this point except being patient for three or four weeks.             Let’s cover some reasons why this might happen so it might be prevented in the future. The damage could have originated from you or your neighbors. This type of damage is a common occurrence during the spring and the fall months because these are the most effective times to apply weed killers. Sprayer Not Rinsed             First, never use a sprayer or spray bottle that contained weed killers to spray insects or diseases. You should have two separate sprayers or bottles; one clearly marked and used for “Weed Killers”. Weed killers are extremely difficult to clean from a sprayer or spray bottle once it’s been used for that purpose. If there is some weed killer residue that remains after washing, then voilà, you just damaged plants that you sprayed for controlling insects and diseases! Spray Drift             Secondly, you or your neighbors should never spray weed killers when there is wind. If you must use a weed killer, look at the tallest trees in the neighborhood and see if their leaves are moving. If they are, do not spray weed killers. The best time to spray weed killers is early in the morning before the wind has kicked up and it starts to get warm. Heat             The word “warm” takes me to the third rule; never spray a warm surface or when air temperatures are warm or hot. Landscape rock mulch heats up quickly as soon as the sun comes up. On a warm day, these surfaces reach 150°F or more by 9 AM on a sunny spring day. When weed killers are sprayed on hot surfaces, they volatilize and move to the neighbor’s yard with the gentlest air movement and can cause plant damage.

Q. I am growing hot peppers in big plastic pots with soil for vegetables I bought from a local nursery. The plants grow fine but the blossoms dry out and fall off without setting any peppers. They get plenty of water, not too much, and the bottom of the pots are drilled out for drainage. Soil mixes like this Rejuvenate Soil Mix should have quite a bit of compost mixed in it for growing vegetables. A. Growing plants in pots is difficult in the hot desert. The major problem is overheating of the soil. The side of the container facing the sun can reach 170° F and kill half the roots inside. Losing half the roots of a plant can be quite stressful and cause flower drop. You can kill a lot of roots with a bad soil mix, poor drainage and watering too often, but it doesn’t sound like that’s what’s happening. Five gallon nursery containers are big enough if you water early in the morning and they are on the east side.  Make sure the container is large enough. Five-gallon nursery containers are large enough if plants are watered daily, sometimes twice a day when it’s hot, and the soil stays cool. I have had luck with this size container growing vegetables and herbs if on the east side of a building so the container is shaded in the afternoons. Containers may be shaded by other containers or a vegetable bed. But larger, 15-gallon containers work better. A single cabbage growing in a five gallon nursery container             Water just before the container gets hot. Moist soil is harder to heat up than drier soil. This is because the water in the soil absorbs heat. I will usually water between 7 and 9 AM.             Double pot the container. Putting the growing container inside an outer, more decorative container shades the inside container and protects plant roots. This is called “double potting” or “pot-in-pot” container growing. If the containers are the same size and shape, put a layer of pea gravel 2 inches deep in the bottom of the outside container so they don’t lodge.             Plants grown in the double containers for more than one growing season should be twisted a half turn every month to break off roots growing through the container into the ground.

Q. I have an Ocotillo plant that is now sprouting beautiful flowers and leaves. I have been watering it with a mist spray near the top. Now that it is in full foliage can I turn of the mist and just water at the base once a week? Ocotillo and myoporum went through a rough winter in 2013. This was probably January after a good freeze. A. I have never been a big fan of misting plants like Saguaro, Joshua Tree or Ocotillo. It doesn’t hurt anything, but personally I think it’s a waste of time. The effects of misting last less than 10 minutes in the desert. Ocotillo stem cuttings will grow roots in soil that drains without any misting if they are watered regularly in the spring. Ocotillo growing in the Sonoran Desert. Although not found in the Mojave Desert, Ocotillo can be found on the edge of the Sonoran and Mojave Deserts nor far from the Colorado River.             Now that the leaves are out, turn over the watering to the roots. If it is newly planted, moisten the soil each time you water close to the trunk or stem. A basin or donut constructed around the trunk helps contain the water. Fill the level basin with 1 to 2 inches of water each time you water. Remember, these are desert plants so don’t water them as often as non-desert plants. If you do, you can kill them. A good sized Ocotillo growing at a Las Vegas residence.             In about one month, increase the size of the basin or apply the water over a larger area to encourage the roots to grow further distances from the trunk. Watch the growth of your plant. Adjust your watering intervals to encourage or discourage growth.

Q. I received a Thornless Blackberry plant as a gift from an online nursery. Can I grow this blackberry bush in our yard? We have lots of rabbits and birds visiting all the time. Blackberries growing in NLV Nevada at the University Orchard. This was either Rosborough or Womack. They are very similar. A. I have grown blackberries in the Las Vegas Valley. Some varieties of blackberries perform better in the Eastern Mojave Desert than others. Some varieties struggle with poor growth and scorched leaves in our climate and soils while others don’t have the same issues. Either Rosborough or Womack at the University Orchard.             You don’t mention which variety you have, but I had success with ‘Womack’ and ‘Rosborough’ varieties out of the Texas A&M breeding program but not ‘Brazos’ which came out of the same program and was successful in Florida. I have had poor luck growing any varieties coming from the Arkansas breeding program. They mostly have Native American names like ‘Arapaho’, ‘Apache’, ‘Comanche’, etc. Rosborough or Womack blackberry at the University Orchard in NLV, Nevada. Aside Blackberries are divided into trailing, semi-erect or erect types. These blackberries were semi erect so I had a wire trellis for them mostly to keep them upright. Blackberries can also be divided into thornless or ouch. Mine were ouch! They definitely had thorns. I learned to prune them soon after harvest because it was difficult to figure out which ones had berries that year (floricanes) and which ones I needed to leave for next years production (primocanes). The canes would grow a little over five feet tall and they were flooded in a sunken irrigated bed with bubblers. After I left, the Orchard manager tried to pull them out but there were still some root remnants in there a few years after I left.             Don’t expect the same quality berry as you might get from the Pacific Northwest and they don’t keep as long in our desert heat of May. Blackberries will be ready to pick in one day rather than two or three days as they are in cooler climates. This means, like figs, you must check blackberries every day when they are close to mature.   Womack blackberry at the University Orchard probably close to May, 2004             I would grow blackberries as a novelty but don’t expect miracles. Amend the soil with good compost at planting time and water regularly.  Cooperative Extension at Arizona State University prepared an online fact sheet on blackberries from some research done in Yuma, Arizona. 

Q. I want to give my son a housewarming gift of a Butterfly Bush for his new home in Summerlin. Would there be any special care for growing that bush here? A. I think you are referring to the Butterfly Bush, Buddleia davidii. This plant is grown successfully further north, commonly in the Northeast, mid-Atlantic, and Midwestern states. It is meant to be grown in cooler, wetter climates and not intended for the desert. Will it grow here? Probably, if you plant it in the cool microclimate part of the landscape and give it some TLC.             There is another Buddleia, Buddleia marrubifolia, and called the Woolly Butterfly Bush, that does do well here and is attractive to butterflies but may be hard to find. B. davidii vs B. marrubifolia             In the desert there are better choices for attracting butterflies, if that is your intention, including Jojoba, any of the native Senna, Bottlebrush, Saltbush, Lantana, Goji or Wolfberry, Red Bird of Paradise and many others. Arizona Plant Lady on Butterfly Gardens University of Az on Butterfly Gardens