Sago palm has changed very little over millennia

A: You don’t do anything. Let nature take its course. The cycad, aka sago palm, comes in both sexes. The male sago palm has a flower that is more cone-shaped, usually pointed and upright at the center. The female flower is more flattened and spreading. Your female flower will eventually disappear, and the new fronds in the center will lay down, hiding where it appeared and should become the same size as the older fronds.

These plants are considered ancient representatives of their kind and have changed very little over the millennia. They are, like pine trees, true gymnosperms.

Because they are not desert plants, they grow better surrounded by wood mulch rather than rock mulch, and they like fertile (organic) soils, not desert soils. So, these plants grow better in cooler eastern parts of the landscape with the soil amended with compost and covered with decomposing organic wood chips that continue to enrich the soil. Rock mulch does not enrich the soil.

Q: I have a small courtyard (12 by 12) at the entrance to my home that was redone with decorative pavers by a local contractor. I have a fig tree planted there, and they had to remove one very large root and several smaller roots to install the pavers. I don’t want the pavers to buckle from new roots growing. Should I remove the fig tree or take a chance the roots will not ruin the pavers in future years?

A: There is no guarantee the fig tree roots will not buckle the decorative pavers in the future. You can decrease the chance this might happen by doing two things: deep water the fig tree when it’s irrigated and install a root barrier to deflect the roots, which oftentimes decreases the chance of having surface roots.

Watering a fig tree deeply but infrequently to an area equivalent to at least half of its canopy — rather than giving it frequent shallow irrigations — encourages deep root growth and discourages roots from growing just under the pavers. The soil or sand a few inches from the pavers should dry out as the next deep irrigation approaches.

Dry soils discourage root growth. Moist deeper soils encourage root growth. Finding the right irrigation cycle — how often to water seasonally and how much to apply each time — will be tricky at first. But once you find the seasonal “rhythm” of applying water to this tree, it becomes less difficult.

Another option is to not worry about irrigation timing and relegate yourself to cutting off roots every three to four years that grow and heave the pavers. Fig roots are prolific and grow back easily once they are cut off.

The secret will be to make sure there are deep roots to compensate for periodic removal of the shallow roots. Most plants can tolerate the removal of 25 to 50 percent of their roots during the winter with no apparent visual damage. Make sure the pruning saw is sharp and disinfected before cutting.

A third option is to install a root barrier — one manufacturer is called Deep Root — that deflects the roots and decreases the chance of heaving the pavers. There is some discussion about their effectiveness. Installation of root barriers is common when trees are growing near walls or other features, called hardscapes, that can be expensive to repair if damaged.

Make sure a porous fabric weed barrier is installed under the decorative pavers. I would highly recommend filling the spaces between the pavers with a porous jointer, landscape or polymeric sand rather than mortar so the roots of the fig tree can breathe. Never use nonporous plastic sheeting applied under the pavers as a weed barrier.

Q: Where can I buy bare-root fruit trees?

A: Bare-root fruit trees have no soil surrounding the roots but instead are available with wet shredded or wood chips surrounding the roots to keep them fresh. The trick in planting them is to keep the roots wet or moist upon arrival and during planting, amending the soil, planting at the same depth they were growing and staking. If you have a brown thumb, then I would stick to planting containerized fruit trees. They are more successful for the inexperienced gardener.

The reason container-grown plants were developed was that people lost touch with how to plant bare-root plants and consequently encountered plant death. Locally, all you can buy are fruit trees in containers.

Belonging to an active local garden club can provide plants that members have grown or gave them some measure of success. Plus, members can give you many helpful tips on caring for them.

The only way I know to get bare-root fruit trees locally is by ordering them through a website for local delivery. Mail-order nurseries have improved tremendously over the past 15 years. Mail-order nurseries open their door for orders around September of the year prior to planting.

Specify bare-root fruit trees to be delivered to our location and elevation starting in mid-January and delivered no later than mid-February.

Dig the hole and amend the soil before their arrival. Have the hole dug wide and ready to plant the day they arrive. They will arrive in a cardboard box from USPS or FedEx with the roots packed with moist shredded wood fiber instead of soil.

Keep the roots wet. Don’t forget to stake them after planting and provide rabbit protection if living near a golf course or the desert.

If you have never ordered bare-root fruit trees before, some mail-order nurseries to consider might include Grow Organic, Bay Laurel and Stark Brothers. There are many other good ones.

Major reasons for tree death include not amending the soil, failure to dig the hole wide enough, letting the roots dry out, not planting at the proper depth and failure to stake them after planting.

Q: What is the best wood mulch to use around plants in Las Vegas?

A: The best wood mulch is the stuff that’s chipped from local trees. But it’s hard to find. Most of the tree trimmings are taken and dumped at the landfill. What a waste.

One of the reasons local tree trimmings are so important is because they are a mixture of different kinds of wood. This mixture of different types of wood is like gold. I prefer to eliminate trees used for mulch that have big thorns like many mesquite trees and palm trees because their wood decomposes so slowly.

I separate mulches into two kinds: one that you apply to the surface of the soil because it looks beautiful; the second kind is not as pretty, but it’s more functional. The stuff that is not pretty and more functional is chipped from local trees.

I understand the desire for a beautiful or decorative surface mulch, like redwood or cedar, because it looks and smells so good. If you are using a decorative mulch, it’s best to put a wide ring of rich compost down first and then cover it with about 3 inches of your favorite pretty mulch.

About a ½ inch deep ring of rich compost covering the irrigated area (starting 12 to 18 inches away from the tree trunk) is necessary. In about two to three years, apply this layer of compost again by raking this redwood mulch back, applying rich compost and reapplying surface mulch to the same area.

Q: I have a saguaro cactus that is 8 feet tall and no arms developing on it. When should I expect this to happen?

A: Arm development, if it happens at all, will start anywhere from 6 to 9 feet off the ground. Yes, it is possible it might not grow arms at all.

The purpose of the swollen trunk and arms of a saguaro cactus is the storage of water. In the Sonoran desert where rainfall is 250 percent more than the Mojave desert in an average year, they will survive there naturally because of the summer rainfall, which does not occur in the Mojave Desert.

In a landscape setting, the saguaro cactus is irrigated, so there is less need for water storage. Hence, there is less of a need for water storage and arm development.

Saguaro cactus is native to the Sonoran Desert, not the Mojave Desert. The counterpart to a saguaro in the Mojave Desert is the Joshua tree. So, the saguaro cactus is periodically supplemented with water in residential landscapes in the Mojave desert.

Saguaro cactus should be watered no more than about four times a year; two or three times during the summer and once during the winter. The best way to water cactus native to the Southwest is by using a hose and sprinkler rather than automatic timers or irrigation clocks. Don’t use softened water from the house but unsoftened water from a hose bib connected to a hose and stationary sprinkler.

Turn the water on so that it wets an area 8 to 10 feet in diameter. Two or three hours of hose and sprinkler irrigation can water to a depth of a couple of feet, deep enough for this cactus. The roots of the saguaro cactus are not all that deep, but they can spread very wide distances in the desert, up to eight times its height.

Q: Why are the new fronds on my queen palm bending over and not opening when they unfold. I have been watering the same way for past five years with each tree getting about 10 to 15 gallons every other day when it’s hot, so I don’t think it’s the watering.

A: Because the fronds are feathery, queen palms are subject to lots of wind damage when grown in the desert. But if you are confident this damage is not from watering, then try applying a palm type of fertilizer high in magnesium and potassium and see if that stops the production of weakened frond petioles.

On a similar note, queen palms are notorious for developing yellow fronds if nutrients such as iron, manganese and zinc are not available to the plant. Apply compost around the base of the plant or a water-soluble sulfur fertilizer amendment (in hopes of lowering the alkalinity). If fertilizer is selected instead of compost, then make sure the fertilizer contains these micronutrients as well as magnesium and potassium.

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.