Problems with fig trees usually caused by human management
The most frequently asked question asked in 2016 concerned fig trees. Readers wanted to know why their fig trees did not produce good fruit. Either the fruit dropped from the tree when it was small, or the fruit clung to the tree and never became large but remained small, hard and dry.
There are hundreds of local fig trees that produced fruit consistently for 20 plus years in the Las Vegas Valley. In most cases, these problems are a human management problem, not the fault of the tree or the climate.
Fruits of fig trees are “multiple fruits,” similar in basic structure to fruits of pineapple and mulberry. Multiple fruits have dozens of flowers produced in a cluster at the end of a fleshy stem. Each flower produces fruit that expands, growing into each other, as they get larger. This type of growth produces a single, large fruit composed of dozens of smaller fruits.
Fig fruits are strange. When picturing fig fruits, think of a pineapple turned inside out, miniaturized with fleshy, moist fruits on the inside and a more durable core on the outside. Pretty cool adaptation for dry, harsh climates.
Figs originally came from drier parts of Asia and transported to the Middle East perhaps more than 10,000 years ago. Growing figs by humans predates wheat. Once transported and grown in deserts, they no longer could survive and produce fruit without additional water. The tree would survive and grow but could not support a crop of fruit without additional water. It needed irrigation to be productive.
Fast-forward to the Mojave Desert and the planting of fig trees. Fig trees do not need much water to survive year after year. But like any other fruit tree, it needs additional water to support a crop of figs. As the tree gets larger, it needs more and more water to support this larger tree plus a crop of figs.
If your fig fruits are not good quality, it is most likely not enough water. If the tree is allowed to get big, and it will, add more drip emitters or enlarge the water basin around the tree. Put a 4-inch layer of wood chips around the base. Or make it smaller.
Fig trees can be pruned without mercy. They will recover from a stump if they must. Keeping the tree smaller requires less water for irrigation. Prune it smaller in December and January but keep some of the growth from 2016 if you want an early crop of fruit.
Q: What are the proper measures when transplanting a mature 10- to 15-foot tall pomegranate tree. Once transplanted, what to do that betters the chances of a successful transplant?
A: In a few words, take as much of the roots with it when you move it. That is tough to do by hand and rough on the tree regardless. Use a backhoe or, better yet, a hydraulically operated tree spade. There are a couple of arborists in Las Vegas who own tree spades who could do it for you. A tree spade is by far the best way to move a larger tree.
Digging it up and moving it by hand is difficult unless it has been on drip irrigation or prepared for this move one year in advance. A successful transplanting moves as much of the roots as possible to its new location and at the right time of year.
December through February is the right time of year. Drip irrigation keeps tree roots closer to the trunk. With rainfall, or a landscape irrigated by sprinklers, tree roots spread wherever there is water up to twice the height of the tree.
This means a 10-foot tree might ideally spread its roots 20 feet from its trunk. Unfortunately, the most important roots to transplant with the tree are roots growing at the outer half of its root spread. That’s not possible.
Older trees on drip irrigation, or irrigated with a depression around the trunk, have a better chance of survival because more of their roots are close to the trunk. You might not have many options open to you, so let’s cover what to do for worst-case scenario.
First, cut the limbs back so they are 3 or 4 feet tall. You must remove at least one-third of the tree’s canopy when transplanting. Next, dig a vertical trench around the entire tree deep enough to sever all the roots in the top 18 to 24 inches. This trench should be at least 2 feet from the trunk.
Dig the new hole for the tree. Dig it twice the width of the trenched hole and about 6 inches deeper. Mix compost with soil taken from the new hole. Use this soil mix when replanting the tree.
I am not a huge fan of the product, but add Super Thrive to the backfill. It’s relatively cheap insurance.
Undercut the trenched tree so it moves freely back and forth. It would be perfect if all the soil attached to the roots was moved with the tree. But most of the soil will fall free from the roots when it is moved. Not perfect but it’s OK.
Lift the tree from the hole and cut any remaining roots with pruning shears (best) or a very sharp shovel. If most of the soil fell from the roots during the transplant, get the tree into its new hole and watered as quickly as possible. Minutes of delay could prove important in the speed of its recovery.
Begin backfilling around the roots with the soil mix you created and water from a hose at the same time. The soil should be a slurry and fill all of the voids around the roots. Filling these soil voids is important.
Equally important is to stake this tree so its roots are immobilized for one growing season. Construct a basin around the tree at least 4 inches deep and on top of the new hole. Fill this basin after transplanting three times over a period of one to three days.
Water once a week, filling the basin, for the first month. After the first month, water it as you would normally or as needed.
Q: I have daffodils and Dutch iris bulbs shooting out new growth this past November. Each year they produce leaves in the fall but never flowers. Are they confusing this time of year with spring? What should I do?
A: This type of oddity — flowering at the wrong time of year — happens with some plants. Sometimes we see it in fruit trees such as apples, pears and even grapes. Plants are more in tune with their environment than animals, and these environmental clues can sometimes mislead them.
Plants that originate from temperate climates, climates with seasons, use two environmental triggers to gauge when to flower and produce fruit. These two environmental triggers are cool or cold temperatures and unbroken darkness for long periods. This works great in the spring.
A primary mission of plants is to survive and produce offspring. Producing flowers will produce fruit that produces seed. Spring flowering, not fall flowering, is extremely important for temperate plants. Flowering in the fall does not give most plants enough time to produce the seed needed for reproduction.
If one or both triggers are activated at the wrong time, the plant may be “tricked” into thinking it’s spring. Every fall, the length of nighttime mimics the length of nighttime in the spring. That’s one trigger. If there are unusually cold temperatures in the fall, then both triggers could activate flowering.
What to do? Remove the flowers when you see them. Otherwise, leave the plant alone. Flowering in the fall is not a big deal, but fall fruit and seed production are a huge drain on plant food supplies needed for next spring.
Bob Morris is a horticulture expert living in Las Vegas and professor emeritus for the University of Nevada. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.
