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Plant Problems

There can be times when you're looking at a plant, and it just looks wrong. You aren't quite sure what it might be, specifically, but you think that, maybe, it feels unhealthy. Now this can be any kind of plant - from that stately tree in the yard, to the lettuce in your veggie plots, to one of your favorite houseplants in the window.

Often, you want to call the master gardener help line for information, but what if you're not even sure what to ask.

Here's a few pointers to give you some direction, before you call for help.

It might be easiest to look first at the plant, and then at the environment where it's been living.

What is it about the plant that seems - wrong?

You should usually look at the leaves before any other part.

Are they the right shape? Can you see any deformity? If so, look closer. Curled leaves or twisted ones often mean that insects or mites have set up housekeeping. Little fluffy white masses on the underside of the leaf, or where the leaf is joined to the plant, indicate a particular problem insect that's a real problem on cactus.

Are there holes in the leaves? Are they small, with a yellowish halo around the edge? That frequently means there's a disease at work.

Are the leaves the right color? Are certain areas of them discolored? One widespread problem we have in the desert southwest is due to alkaline soil. The veins in the leaves stay green but the rest becomes pale, maybe even white. Or perhaps the perimeter of the leaves is yellow. Any of these can be due to nutrient deficiencies.

Support comes from

Is there are a difference in the leaf color at the top of the plant, that's the newer leaves, from the ones at the bottom, the older leaves? That can be due to a deficiency of some nutrient, but it can also mean something completely different, poor drainage.

After the leaves, look at the overall plant (which, remember, could be a tree, a shrub, the philodendron on your windowsill). Does it look like the problem is spread all over, or is just in one area? See if there's a broken limb. If you're lucky, the problem might be something you can just prune away.

Not only do you have to look at the plant, but you need to check out its surroundings. If you touch the soil, you should be able to tell if it's too dry or wet. How often do you irrigate? Have you watered this plant? How often? Is it sitting in water? Like I've said umpteen times, poor drainage is one of the most common causes of plant death in Southern Nevada landscapes. Or landscapes anywhere, for that matter.

How deep, and more important, how wide was the hole where you put that tree or bush? You've heard that the hole should be no deeper than the plant you're putting in it, but it should be three to five times as wide. It almost sounds counterintuitive, but shrubs and trees do so much better under those conditions.

Some plants get put in places that are just too hostile for them. Several plants that will survive if they're protected, say in a north facing situation, will fry under conditions of hot, western light.

Many of our favorite indoor plants originated in the tropics.

They thrive with lots of warmth, but they also need high humidity. Have you been providing that? - remember, it doesn't come naturally in the desert. Occasionally they'll get scorched if they're too close to a very sunny window.

Have you fertilized your plants? Soils in the desert southwest are notoriously infertile. Your fertilizer can be your own compost or something you pour from a can. A fertilizer that's listed as 'all-purpose' will frequently give plants a boost. It won't cure diseases or repel insects, but healthy plants are much better equipped to deal with them.

Have you used an herbicide anywhere? Worse yet, has one of your neighbors used one? This would have been a particular problem when our temperatures were up to a gazillion degrees for weeks on end. Many pesticides have an advisory that gives the upper temperature limit for use. Spray something when it's warmer, and you cause problems as it drifts away, off target and doing all kinds of damage. I've even heard of people using herbicides when they should have used an insecticide, with disastrous results.

There's a host of reasons for plants to look forlorn, but looking closely at them will give you a head start on solving the problems. At least it'll be a start if you search for help from a Master Gardener.

For KNPR's Desert Bloom, this is Dr. Angela O'Callaghan of the University of Nevada Cooperative Extension.

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Tuesday, September 13, 2005
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