Container trees have problems retaining water, fertilizer

Q: The leaves on my 3-year-old almond tree, planted in a container, started to dry out quickly due to a problem with drip system. To compensate, I hand-watered but apparently not enough. Once the system was remedied, very small new leaves starting to grow. Will this tree survive the coming cooler weather? I watered heavily and applied a tree and nut fertilizer.

A: I have seen this before on young almonds planted in the ground, and it is usually, like you stated, an irrigation or drainage issue; the leaves dry up, turn brown and drop from the tree before winter. Once the leaves are without water for a day, the amount of hand-watering you apply will not save any of the leaves. The leaves are goners. But the buds already formed for next spring will grow instead, usually no flower buds just leaf buds. That’s what happened to your tree.

The tree will have no problems surviving the winter, with or without fertilizers, if the soil is moist and drains water. That’s not the issue. They used up buds saved for next spring. That’s the issue. Hopefully, there is enough time remaining for the tree to grow new buds before it gets cold. If not, you might see a delay in leaf development and flowering next spring.

Trees grown in containers are more finicky than those planted in the ground because the roots don’t have access to as much soil mass. The limited soil volume in containers makes watering and applying fertilizers more complicated; the tree runs out of both more quickly. Watering and fertilizer applications are in smaller amounts but applied more often to compensate for the small amount of soil.

Almonds put on a beautiful floral display in the spring. I can see why you wanted it in a container. Hopefully, you planted a dwarf almond-like Garden Prince or All in One and used a large container. Remember it needs to be repotted every few years to keep it vigorous.

Q: I have a kumquat citrus tree that has been in the ground for eight years. During the last two years, a lot of leaves fell off in the fall, leaving some branches leafless. Yet some branches stayed green with new shoots coming out. What might be the cause of the problem?

A: The tree, from the pictures you sent, looks dense and full, with a few “blind” shoots here and there. The tree might be too dense. Leaves need sunlight and produce a net energy for the tree to stay productive and healthy. Rather than leaves producing energy for the tree, leaves growing in total shade will be dropped from tree limbs because the tree must expend energy to keep them.

I would open the tree canopy to admit light to the inside. That will encourage fruit to develop throughout the canopy rather than just at its edges where there is light. Do this by total limb removal with thinning cuts. Prune so that limbs are 4 to 6 inches apart, not growing on top of each other.

A trick to know if there is enough light penetrating the canopy is to look at the tree’s shadow on the ground at noon during midsummer. The shadow created by the canopy should have speckled light throughout it. If an area of the shadow is totally dark, then this is the area of the tree that needs to be pruned to admit more light. Admitting more light allows better fruit production throughout the tree canopy, and removing a few limbs here and there during the summer does not hurt the tree.

Otherwise, you might be giving the tree water and fertilizer, particularly nitrogen, too often. Water when the soil moisture is starting to dry. On a soil moisture meter this would be an average of “5” on a 10-point scale at a depth of about 4 to 6 inches and measured in three different locations. Never water daily. Apply water to at least half the area under the tree canopy and apply enough water to get it 18 inches deep.

Q: After reading about the many desirable qualities of screwbean mesquite trees, I am determined to plant two of them in my yard. However, today I searched the nurseries and discovered there was none to be found. One nursery offered to order them for me. I would rather see what I am buying. Do you know of any place that carries them? Do I have to start my own from seed?

A: Screwbean mesquite is a very nice small desert tree native to Southern Nevada but not in high demand by the public. So, the local nurseries typically don’t carry them. It’s a “chicken vs egg” problem in marketing and sales. Some nurseries will order them for you, and that’s nice they offer that service. You may or may not be able to see the tree ahead of purchase going this route. Ask.

Locally, try the State Tree Nursery at Floyd Lamb Park and check the availability there. It has a website and posts plant availability, but it doesn’t hurt to give them a call because not everything is posted.

The tree is easy to propagate from seed, cuttings or marcottage, but for the inexperienced gardener, probably seed propagation is the easiest method. Just remember, all tree seeds in the mesquite or legume family will have a hard coating surrounding the seed that prevents accidental germination. You must damage this seed coat for good germination.

Pick seed from pods hanging from good-looking trees in midsummer or when the pods are brown. Open the pods and pick 10 of the largest seeds you can find. Damage the seed coat with sandpaper, small file or razor blade with as little damage to the seed as possible. Soak this seed in warm water for a few hours to get germination started.

While you’re waiting, fill a clean nursery container with potting soil to within 1 inch below its top lip. Plant the seed ½ inch deep and 2 to 3 inches apart. Keep seed moist but not wet. Don’t water too often.

Q: I have vines producing melons during the summer. They wanted to split, and the taste was bland. But the same vines producing melons in the fall were much sweeter. Can we conclude that when it is too hot, sweetness suffers and splitness reigns?

A: I wish it were that simple. It’s really a question of the type and variety of melon grown as well as time of year.

During times of high water use, some types of melons easily split. Splitting is usually an irrigation issue; soil gets dry followed by an irrigation. That happens frequently in the desert when growing in uncovered, bare soils.

Water loss from the soil can be over 4/10 of an inch per day. This is about 50 percent higher than water lost from the same crops in melon-growing regions. It helps if you make sure the soil is not dry when it enters the hottest time of the day.

Melon splitting is a variety issue complicated by weather and climate. If splitting is a problem with a variety, then select sequential planting times or choose a different variety. It can make a difference. Write down your choices in a garden calendar and learn from these notes.

Never harvest melons that do not separate from the vines easily. Melons can be harvested early, and they will ripen, but they don’t get any sweeter than when they were separated from the vine. That is not true of many tree fruits. You can have a fully mature melon that is not sweet if harvested too early.

Melons are hungry crops and can deplete the soil of nutrients quickly. That’s why it will be necessary to add nutrients back to the soil at least yearly.

Some varieties and types of melons just don’t perform ideally during our hot summer months. If you grow tomatoes, that might sound familiar. The heat is great for helping the plant make sugars but not in developing acidity. So, in the future keep good notes, pick varieties of melons that are consistent quality producers, plant them so fruits are harvested during cooler times of the year and wait to harvest until the melon slips easily from the vine.

Trials can be fun, but I would caution you about putting all your eggs in one basket. Rely on a proven variety that you like and combine it with something new. And don’t rely on one season of growth. It can be a bad year. Three seasons are better, and five are best.

Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.