Cactus cuttings should heal first before being planted in ground

Q: I want to propagate my prickly pear and bunny ear cactus. Should I place the cuttings immediately in the ground or in a pot and plant them in the ground later?

A: You can plant cuttings from them directly into the ground. Forget the pot. It’s not necessary. Wait until March or April, when it gets warmer.

Remove a pad from the plant you are propagating and let the pad with the cut end heal in the shade for about a week. To do this, take a sharp, sterilized knife and bend the pad over without breaking it.

Touch the sharpened edge of the knife to the suture where the pad joins the mother plant. The pad should pop right off at the suture. If not, gently push the sharp edge of the knife into the suture and slice through it smoothly.

If you really want to guard against infections in the pad, dust the cuts of the pad with a fungicide such as Thriam, copper sulfate or Bordeaux. When you put the pad in the shade to heal, lean it against something so it is upright or the pad will begin curving if you lay it flat.

Mix the soil where you are planting with compost and add water. Stick the pad so the flat sides of the pad face east and west. Sink the pad about one-third of its length into the soil and water it once. After that, water it about every three weeks, and it will begin rooting into the soil where it is stuck.

Q: I have a 3-year-old passion fruit tree in my garden. It started bearing fruit that grew fine and was mature enough to eat in February. In spring, I also had more flowers blooming on the same plant, but these flowers never had any fruit. The same thing again this past summer, but the flowers are not fully developing and are stopping at just little buds.

A: Passion fruit is a semi-tropical vine that can’t handle freezing temperatures very well. It also likes moderate temperatures so it will have difficulties during the hot summer months. It grows very nicely in the tropics and moderate temperatures of high elevations in Africa.

Unless you have a warm microclimate in your landscape, these plants will show serious damage or die from winter freezing temperatures. If you can grow oranges in your yard, you should be OK growing passion fruit vine. Passion fruit may have difficulty setting fruit during the summer months because of high temperatures and low humidity.

Passion fruit definitely does not like soils with poor drainage. If this is the case, and you don’t do anything about it, the vine will always have problems and probably die. Make sure the soil is amended with compost at the time of planting, and cover the area around the vine to a distance of about 3 feet with woodchips so that they decompose into the soil.

Passion fruit flowers are beautiful but they need help sometimes to produce fruit or to produce larger fruit. You may need to hand pollinate the flowers, transferring the pollen from one flower to the next, a job normally done by a variety of different bees.

You may need to grow two different vines and transfer the pollen from the flower of one vine to the flower of another vine. This helps prevent what’s called “self-incompatibility” and failure of fruit to develop.

Passion fruit germinates easily from fresh seed and does well on its own roots. Passion fruit propagated by cuttings has self-incompatibility between flowers and will not set fruit.

Also, prune the vine by removing side shoots after the fruit is removed. This helps the new growth growing from the older wood of the vine where flowers are produced and keeps the vine renewed for more production.

Besides trellising this vine and pruning it back occasionally after fruiting, apply wood chip mulch at its base to preserve soil moisture and keep the fruit from being dropped if the soil gets to dry. Fertilize the plant lightly after it flowers by applying a tomato fertilizer to the soil around the plant and water it in.

Q: What are the best practices to use if I decide to leave calamondin fruits on the ground under the tree to decompose? Or is it better to put the fallen fruit in the trash?

A: Calamondin, called calamansi in the Filipino community, is a small citrus resembling a lime but golden yellow inside. This citrus is native to the Philippines.

Fruit can turn orange in color but is frequently harvested when green but the interior flesh is a golden yellow. We have about eight calamondin on our farm in the Philippines where we have a tropical climate, and they do very well there.

Let’s be clear about growing citrus in the Las Vegas Valley. Many citruses, since they are semi-tropical, share a risk of losing the fruit, or possibly the tree, during some cold winters and early spring freezing temperatures. There are parts of the valley that are too cold most years for even the hardiest of citrus. Other areas with warmer winter microclimates can grow them. As long as you are comfortable with that possibility, have fun and grow them.

In my opinion, all fruit trees should have the area under them free from rotting, mature fruit. Very young fruit is usually not a problem if it falls on the ground and decomposes.

Immature fruit thinned from the trees can be dropped on the ground to decompose with no problems. Mature fruit dropped on the ground may present a different issue.

If this were a peach, fig, apricot or plum tree, we would most certainly clean up the fallen mature fruit that dropped on the ground. There is a pest called the dried fruit beetle that becomes a problem infesting soft, mature fruit growing on the tree if fallen fruit is not picked up from the ground.

With citrus, the only pests to worry about are rats and mice. To be on the safe side, I would pick up fallen fruit and dispose of them rather than leave them on the ground to rot and attract varmints.

By the way, calamondin is easily grown from seed and does well on its own roots rather than purchasing it grafted like most commercial citrus trees.

Q: Several of my bamboo shoots died completely, and now they are all starting to yellow and have a white film on them. Any suggestions?

A: You didn’t say which bamboo it is, but I assume it’s one of the bamboo tolerant of our winter temperatures. The so-called “running bamboo” rather than the clumping types represent those that tolerate our climate better.

The white film is sometimes called a bloom of wax on the outside of the stem and is normal. If these are instead white fuzziness in patches and appear to be a problem, then you might be looking at mealybugs. But I think this white film has more to do with the naturally occurring wax produced by many plants rather than a pest problem.

Yellowing can be caused by water not draining from the soil around the roots and suffocating them because of poor drainage or watering too often. You may be thinking that this plant needs water all the time, which it doesn’t. The soil needs to be kept moist for good growth, but let the soil breathe so that the roots and rhizomes can get air.

Invest $10 in a soil moisture meter for houseplants. As long as the soil is somewhat soft, push the probe slowly into the soil and get a soil moisture reading at the 4- to 6-inch depth.

I would not irrigate until the meter on this gauge reads approximately “6” at this depth in three locations. On these gauges, 10 is sopping wet and No. 1 is totally dry.

The yellowing could be a soil alkalinity problem, but I think instead it is probably poor drainage. When planting bamboo, amend the soil with compost at the time of planting and cover the soil around the plant with woodchips out to a distance of 2 to 3 feet. If drainage is a big problem even after amending the soil, plant it on a mound.

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.