Question: I live in Marana and have been at this address for about 10 years. We have a mature ocotillo on our property that has been here since we moved in. For the first seven or eight years it seemed to leaf out in the spring and after the summer rains, much the same as he other ocotillos in our area. However, the last two years it has been rather slow to leaf out, and so far this year, there are only a few leaves on it, although the orange blooms did appear at the tops of the canes. I have tried to deep water it a few times, and even used a hose end sprayer to spray the canes all the way to the top, (they are about 20 feet tall in places) yet still there isn’t much leaf growth. All of the other ocotillos in our immediate area have seemed to be completely leafed out. My question is, is there anything that I can do? Or should I just give up on this plant and have it removed?
Answer: Ocotillos typically leaf out in response to rain in the spring as well as during the monsoon season if they receive enough. It’s hard to be sure why individual plants leaf out normally one year and then less the next unless there is some change in their surroundings. For example, the growth of nearby shrubs or trees could be shading the plant more in the last few years than previously and it could be sheltered from the storms. Timing of the rain or irrigation may have some effect. I wouldn’t give up on the plant if it were still flowering. For native desert shrubs in the landscape, irrigation once every two to three weeks to a depth of 24 to 36 inches in the spring through fall is all that is recommended.
Q: We had a mountain ash tree delivered in late March from and planted by Moon Valley Nurseries in Chandler. We had selected it (fully leafed and green, 24” container, about 13’ tall) in person 2 weeks prior to delivery but when it arrived one entire half of the tree had broken small branches and brown, wilted and crumbling leaves. Moon Valley said it was windburn and that it happens to all trees that are in transportation for the 1½ hour trip on the truck, covered by a tarp. We were quite shocked by the condition of what originally was a gorgeous tree, having paid $500 for the tree and planting, $100 for a 1 year insurance policy and $300 for delivery from Chandler to Oro Valley. The tree has now new growth leaves (along with remnants of browned and dried out leaves). Moon Valley has since refunded $100 of the $300 transportation charge. After we contracted with Moon Valley for the mountain ash I happened to find at Home Depot a beautiful fully-leafed-out Arizona ash, 24-inch container, about 12-feet tall with crown diameter of 6-8 inches and brought it home (only a 2 mile trip) upright in pickup and we planted it ourselves. The foliage stayed green and supple throughout the wait to be planted and the planting process and has since added extensive new growth. I just want to confirm with an expert that what we were told by Moon Valley, after the fact, about the inevitability of windburn is correct.
A: I suppose you could say there is inevitable “windburn” on a tree delivery if they leave it in an open truck while driving down the highway at 75 mph for 90 minutes. The leaves shouldn’t be brown unless the branches were broken for a while so that makes me wonder how long it was riding around in that truck before it arrived at your house. At least you still have your $100 insurance policy. If the tree fails to thrive, you can always ask them to take it back and replace it with a new one. Don’t be surprised if your new trees take a while to adjust to their new surroundings and put on significant new growth. Transplanting is stressful for trees and they often show very little growth in the first year.
Q: The new growth in the mountain ash I mentioned above and have pictured below has many leaves with holes in them. When I checked online about this I read that it was a sawfly and could be treated by spraying the tree with certain type of pesticides depending on how heavy and how late the infestation. I hadn’t seen any green caterpillars with black dots so I called Moon Valley Nurseries. I was told it was a “beautiful act of nature” in that it was a queen bee making her nest near the tree and feeding off the leaves. That it wouldn’t hurt the tree (aside from making it look afflicted — my opinion) and that I should “NOT kill the bees or destroy the nest because bees are endangered and if bees disappear from the Earth human life will also be exterminated.” So the question is first, can you tell by looking at the leaf hole what might be the cause of it and if I can do anything about it that won’t help “exterminate the human species” about which Moon Valley so fervently warned me!
A: Part of their explanation is true; a bee cut those circular holes in the leaves to make her nest, it is a beautiful act of nature, and it won’t hurt the tree. Yes, you can tell by looking at the holes who damaged the leaves. These insects are fairly good at making circles, something that some humans can’t do as well, and they tend to select certain types of plants. The leafcutting bee (Megachilidae species) uses the leaf parts to make her nest rather than feed on the leaves. She isn’t really a queen in the same way that honeybees have queens to run their colonies of thousands of workers. Leafcutting bees are what we call solitary nesting bees and each female makes her own nest. So she is probably more appropriately called the lady of the house. We depend on bees to pollinate a wide variety of plants so it is important to keep them safe. The best thing to do in this case is nothing and everybody lives happily ever after.