Dear Neil: My azaleas are dying, one after the other. This has been going on for the past year. Is this a disease? Is there anything I can do to stop it?

You didn’t mention where you are. In this day and age of online readership I must guess when I’m not told. If the soil is neutral or, especially, alkaline, that would be much to the detriment of azaleas and other acid-loving plants. They simply can’t get enough iron to meet their needs. Your cannas seem to be suffering a similar fate. It almost looks like this bed may have been overrun with water at some point. It looks like silt deposits on top of the stones. It also looks like the bed may be in a hot, reflective location as judged by the angel wing begonias in the wire wall basket. The entire area may need a redo of bed preparation with addition of a great deal of organic matter. If you’re going to try azaleas again, have the soil tested and if it shows a pH of less that 6, replace it with a combination of sphagnum peat moss and finely ground pine bark mulch 15 to 18 inches deep, part of it below grade and part above. You won’t want to run that up against your brick, so I’m not sure that’s going to work in this exact location. You might be better served by dwarf hollies here. They can handle sun or shade and they’re more forgiving of a variety of soil pH ranges. Talk to a Texas Certified Nursery Professional once you get the facts of your local soil.

Dear Neil: I bought my Meyer lemon tree last year and put it into this large clay pot. I know I’m supposed to prune it to shape it, but I can’t see how to do so. Please advise.

You’re going to need to remove any of the branches that are determined to cascade downward over the edges of the pot. Your tree needs to develop 2-3 strong, essentially straight trunks by pruning to remove anything that doesn’t look like “a strong, straight trunk.” You may even need to stake the trunks you intend to save as the plant’s main stalks. Do not allow fruit to develop for a year or two. It would be so heavy that it would weigh down the trunks and probably even break them. And, as you can tell by my photo of our son’s Meyer lemon in California, you’re going to need a much larger pot. For the time being you may want to revert to a large plastic or hard rubber pot to make moving the plant around a lot easier. Eventually you’ll face the decision of planting it into a protected location where it can be sheltered from extreme winter cold. For now hopefully we can get you that far.

Dear Neil: When I hear the recommendation for an all-nitrogen fertilizer for my lawn and landscape plants, does 21-0-0 fit that description?

Be careful. Technically, yes, but that is not a good plan. I generally try to include the longer phrase “a high-quality, all-nitrogen fertilizer with 30 to 40 percent of the nitrogen in slow-release form.” The one you mentioned is ammonium sulfate. While it’s 21 percent nitrogen, every bit of that nitrogen is instantly water-soluble. That results in a surge of vigorous growth, followed by a complete drop-off two weeks later. The better fertilizers, by comparison, have half of their nitrogen encapsulated or coated and waiting in reserve. You still get a nice green-up from the fast-dissolving portion, but subsequent rains will activate the rest. It’s a bit like distance runners who pace themselves for the marathon instead of tearing out of the blocks at full speed.

Dear Neil: I saw recently where you wrote that Bradford pears have bad branching, and that they only last 15 or 20 years before they split. What do you think of Callery pears?

Oh, no! Callery pears are the rootstocks of Bradfords and several other types of grafted pears. They’re reasonably attractive trees, but they don’t have the handsome growth form of the Bradfords, plus they have very long thorns. They tend to send up shoots freely from their roots, and the small, inedible pears they produce are messy underfoot. They also are eaten by birds, and the seeds get planted virtually everywhere. They become terribly invasive. Run from it! All these pears, Bradfords included, need to be struck from our lists up for consideration.

Dear Neil: I recently saw Scarlet’s Peak yaupon holly in a nursery. What is the difference between it, Will Fleming, and Sky Pencil hollies?

They are similar in their very upright, columnar habit of growth, but Scarlet’s Peak and Will Fleming are more universally adapted to both alkaline and acidic soils. Sky Pencils are adapted only to acidic soils. Scarlet’s Peak also bears fruit abundantly. It’s the best of the bunch.

Dear Neil: Is there anything I can do to make a mulberry that produces messy fruit stop producing them? What are the “fruitless” mulberries people have?

Fruitless mulberries are vegetatively propagated to ensure they will all be fruitless. What you have is a seedling tree.  They are extremely prolific, coming up all through our landscapes and even in undeveloped properties – anywhere there is a little moisture. If only there were a spray we could apply to render them fruitless, but there is none.

— Have a question you’d like Neil to consider? Mail it to him in care of this newspaper or e-mail him at mailbag@sperrygardens.com. Neil regrets he cannot reply to questions individually.