Succulents don't require daily irrigation


: I have a Vera Jameson sedum that has grown and spread. However, the plant leaves in the center are dying. I have planted this in the front yard where it receives full sun all day. I water it every day for four minutes in the morning with a shrubbler. I have placed rubber mulch around the base of the plant and two days ago I added some liquid plant fertilizer that I diluted in water.

I also have a Spanish bayonet yucca that the bottom leaves are turning brown from the tips. The trunk looks healthy. This also is receiving full sun and I have been watering it for four minutes each day on a shrubbler drip system.

A: The sedum is a succulent that stores water in its leaves to help it cope with times when there is no water. The yucca also has the characteristic that it can survive long periods of drought.

When I first read your e-mail, it struck me that the problem was either with the soil or with irrigation. But, after finding out that you are watering every day for four minutes, I think the major problem for you is water.

Four minutes of water does not tell me much. I do not know if four minutes of water is the same as 1 gallon or 1 teaspoon. You should apply enough water so that you irrigate to a depth of 12 inches for the sedum and even deeper for the yucca. The sedum will require water more often than the yucca.

A secondary problem may be salt accumulation for the sedum and possibly rotting roots if you are watering daily. With volumes of water in excess of what the plant needs, the salts will be flushed from the soil. When you do water, try to water more deeply and less often to give the soil and plant roots a chance to breathe.

Both plants will handle a period of time without water just fine, and they should not be watered daily. The yucca can be watered less often than the sedum, but probably not more than once a week. I would think every two weeks should be adequate, but it is hard to know without knowing other things like what the soil is like.

Proper watering and soil improvement will help both plants. When planting desert plants, even though they are adapted for the desert, the soil should be improved to help them grow better. Make sure you incorporate soil amendments at that time.

I am not sure why you applied the rubber mulch but that was a mistake. I would remove it. Instead, if you put down some compost or other organic material and water through this material to the plant roots, I think you'll see some improvement. A couple of inches of organic mulch on top of the soil will help keep weeds down and conserve water. It also will help improve the soil over time as the wooden surface-mulch decomposes.

Q: When I moved here from Virginia, I left behind acres of varied plant life including mass plantings of daylilies, hostas, oriental lilies, plus wildflowers galore scattered across my acreage. I bought a small house here and it has limited space for gardening. I opted to go with xeriscape, but my builder's landscaper messed things up by planting huge trees and shrubs that sought orbital access.

This spring I ripped out my backyard jungle so that I again could walk from one wall to the other, while in the front everything came out except the stupidly mandated tree. I want to put in some colorful plantings that would give my little desert some personality. I would like to know if coreopsis, gaillardia, echinacea or even a daylily or two might work here in this climate without raising my water bill too much.

I've even thought about planting some bulbs like amaryllis or canna, but I don't want to plant them and then have to dig them up and haul them into the house each fall since I am 82 years old. I would rather put them in pots and place them on the porch, but I have been told that the heat will kill the roots if the containers aren't insulated.

A: Everything you mentioned will grow here with the exception of maybe hostas. Hostas, for the most part, are shade loving and do not do well in the Deep South and Southwest. I bet there are some people in town who have had some success with them here, but they are tough to grow in this climate.

If you are going to try hostas, then try fragrant hostas like Aphrodite, Fragrant Bouquet, Guacamole and the like. The fragrant hostas usually can handle a bit more sun and probably a bit more heat. But keep in mind that this is an experiment and the plant could very well fail.

If you decide to plant any of the plants you mentioned, I have some recommendations. Put them in a part of the yard that is protected from late afternoon sun, away from a hot west- or south-facing wall where they will get reflected heat, and protected from wind. East- or north-facing (provided that north-facing does not get late western exposure) locations are best. They will do much better with filtered sun but not total shade. You will see more flowers and the plants in general will look more healthy.

Secondly, plant them with lots of compost mixed in the soil.

And thirdly, do not cover the soil around them with rock mulch; use organic or wood mulch instead.

By the way, cannas do very well here planted directly in the soil. You will have to divide them every three years or so and give them to some neighbors. Try one called Tropicana if you like a tropical look for the foliage as well as flower production.

Amaryllis is, of course, cold tender and does best in pots that are planted in the ground and brought into the house each winter. They do not survive outside here in the soil.

When people speak of using containers outside, I like to recommend using very large containers or either double potting the container (so that the inside container does not receive direct sunlight) or double potting the container and placing it in the ground. Small containers put in direct sunlight usually will not support plants except cacti, succulents and other desert-adapted species.

Q: I have two fan palms in my yard. One is green and healthy, but the other has some yellowing leaves that also have brown spots on the top and bottom. The tree is still getting new growth in the center. I do not see any insects or their droppings anywhere.

A: I do not believe your palm tree is in immediate trouble. Usually when a palm tree is in trouble, the central leaves coming from the bud are the indicators, not the older fronds. Palm trees do not have many insect or disease problems here, but they do have some nutrient problems.

As long as you see healthy growth coming from the center, I would not be overly concerned provided you are giving these trees plenty of water spaced like you would any other landscape tree. Unlike desert trees such as acacias or palo verdes, these are oasis plants and require more frequent watering and fairly large volumes when they are watered. They should not be watered daily.

A possibility in your case could be nutrient deficiencies. The quickest way to address this would be to use an all-purpose liquid fertilizer applied to the foliage. Of course, the brown, damaged areas will not grow back but you should see a change in the general color of the frond. The liquid fertilizer could be an organic or granular type mixed with water and sprayed on the foliage. Apply it with a spray adjuvant that you can purchase or a small amount of liquid detergent.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at morrisr@unce.unr.edu.

 

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