Star pine can grow in desert, but don't expect to keep it forever

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Question: I would like to know about putting a star pine in my Summerlin yard. Can it grow here?

Answer: Star pine is known by many as Norfolk Island Pine, a plant popular in the past as a house plant in more northern climates. It is sometimes planted outside in warmer, subtropical climates like parts of Florida and California. It is sometimes sold as indoor Christmas trees and is called Star Pine, although not a pine at all, due to its very symmetrical growth, which resembles a star in a birds eye view.

I am never one to say it will not grow here. It will, but only you can tell if it is worth the effort and only temporarily. First of all it is not meant for this climate and our soils. It will get huge, in native stands 150 feet tall but in hospitable landscapes perhaps 40 feet tall by 20 feet wide. It will not like hot, late afternoon sun or any hot and windy locations in the yard and, unless it is in a very protected location, it will freeze out in the low 20s.

So with that in mind, I would plant it, only if you want it bad enough, and find a spot in the yard where it is well protected from winds and afternoon sun. Perhaps even in some light shade. Modify the soil around it with compost extensively and cover the soil, after planting, with a thick layer of wood mulch. The entire area under the canopy needs to be watered and kept moist.

Rock landscape and drip will be a no-no for this plant. Be prepared to cover or protect this tree every night or early morning hours when temperatures are expected to drop into the high or mid 20s (it usually gets coldest just before dawn).

I am not trying to be a wiseguy but when the tree gets to be 15 feet tall or more you may have to build a greenhouse around it or let it die or dieback when temperatures get that low. It may not happen for 10 years, or it may happen in one. It will develop side shoots from the trunk after dieback and will no longer resemble a star.

So if you want to just have fun with a plant, but are not expecting to keep it forever, then plant it. That's what horticulture is all about, having fun with plants, trying and experimenting with new things and enjoy life.

Q: We just Xeriscaped our yard in May so several cacti and agaves are getting established in a rock mulch. We are watering three times a week at 15 minutes a session with 2 gallon per hour emitters. The larger plants have two emitters on either side of the plant spaced about 4-6 inches away from the center. Our soil is well draining.

But I was a bit concerned that after just before irrigating my moisture sensor indicated still wet conditions. But some other plants on the same irrigation line were showing some sunburn and heat stress. Will decomposed granite hold in moisture excessively?

A: You are watering too frequently on your cactus regardless of the rock mulch used. The other problem is that you need to get the cactus off of the irrigation line with other noncactus plants. You could probably hand water the cactus and they would be better off. Eventually you might try to get them on a different valve or just continue to handwater them occasionally as they need it. If you pay attention to your landscape, they will tell you when they need water. You will see them change in appearance.

You have to be careful because different cacti will have different watering requirements and I do not know which cactus you have but once a week should be an adequate middle ground. Don't be afraid to let the soil dry out a bit between irrigations of cactus.

I would back off watering the cactus to at least once a week, perhaps longer. Try once a week first. Right now I am watering Opuntia (nopal cactus) once every two weeks. These are freshly cut pads that have just been planted and have no roots. They are rooting just fine and sending out new growth (nopales) as they are rooting.

When water runs out, they rely on stored water in the pads and they then replenish the water in the pads after irrigation. But again, different cactus have different watering requirements so be careful.

You can ask any of the Master Gardeners at the Master Gardeners Orchard and they have seen our cactus pads (severed pads from the mother plant) being stored in the shade for several weeks, lying on their sides on the ground still sending up new growth.

Decomposed granite, or DG, will hold water if it is finely milled and has all the reject material (called fines or minus) with it. When installing rock mulch and you elect to include the fines (minus), then you should wash the fines or minus through the rock onto the surface of the soil.

I would take a hose with a nozzle and wash the fines onto the soil around all of the landscape plants out a distance of a foot beyond the emitters.

The cactus should not be on the same watering cycle as other landscape plants.

Q: What school do you belong to regarding the watering of ocotillos and Joshua trees after they have been planted. Some sources indicate no irrigation for the first year but regular spraying of the plant, whereas other reputable sources suggest both.

A: I remember when desert landscaping was first installed in Las Vegas. I had a phone call from a very upset little old lady who said her landscaper, who installed the desert landscaping, said it didn't need an irrigation system because it was a desert landscape. Of course everything died and that is why she was upset.

I personally do not believe that misting or spraying is necessary but not irrigating them in our climate during their establishment is a mistake. Spraying or misting them with water will not hurt them, even when it is hot. I do believe that watering the soil around them regularly is necessary for rooting. Too much watering, combined with poor drainage, and you will rot the stems.

What may be different for me compared to others is that I would plant them in a compost amended soil, not pure sand or gravel. My experience has shown me that if your soil is void of organic matter you will see a benefit from moderate additions of organic matter in the planting hole when planting cacti and other desert plants. Just because they come from a desert, doesn't mean they will not do better when given some TLC. Just don't overdo it.

Q: I just read your article on watering from the Tuesday Southwest View. I am going to assume that I am not watering near enough. I am watering every three days the following: 5-inch-diameter queen palms 8 gallons, 10-foot Mexican fan palm 8 gallons, 3-foot sago palms 6 gallons, 3-foot guava bushes 2 gallons, 2-foot heavenly bamboo 2 gallons and 15-gallon Phoenix palms 2 gallons.

A: Thanks for relating your water requirements to the size of the plants. If my column helped you to do that, Bravo! If these are on the same valve I would add emitters to the queen palms and get it up to about 25 to 30 gallons, the same with the Mexican fan palms. I would add more emitters to the date palms (Phoenix) and get that up to at least 8 to 12 gallons. The palms will not require a lot more as they get bigger because their canopies will stay about the same.

I think the sagos and heavenly bamboo are fine but the guava is borderline. The guava canopy will get bigger so you will have to add emitters as it gets bigger or increase the gallonage by changing the existing emitters. You can do that now or later. I think watering three times a week right now is about right.

Q: I would like to plant a magnolia tree or bush in my front yard. However, the area gets the west sun. Will this type of tree or bush survive in this location?

A: I am assuming you are referring to southern magnolia with the showy white flowers. Southern mangolia has been planted a lot in Las Vegas over the years and if you look around you do not see very many of them.

There is a good reason for that. The ones you do see here now are small and they were planted by people like you just a few years ago. The rest are gone. I was watching one in a yard fairly closely for several years in an older part of Las Vegas until it was finally cut down. I am not sure why because it was about 25 feet tall and it really was not in bad shape. It had shade from taller trees around it and it was in a lawn.

This is a tree not meant for our climate or soils. However, you can have fun putting one in and taking care of it. It is not meant for people who want an easy landscape to care for. It will require extra attention and probably not last a long time.

If you really want to mistreat this plant, plant it in a rock landscape on drip irrigation on the south or west side of a building. Now that is cruel. As you can tell, the best would be the opposite; well amended soils, wood mulch with a bubbler and basin irrigation or in a lawn on a protected side of the building.

You would be better off trying a star magnolia. It might have a fighting chance here in a protected patio area with a north or east exposure. It is a very small, beautiful patio tree that can handle some alkaline soils and its size will make it easier to shelter from the climate extremes.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension.