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Saturday - October 01, 2011

From: Houston, TX
Region: Southwest
Topic: Xeriscapes, Pests, Transplants, Drought Tolerant, Shrubs
Title: Cenizos browning in Houston
Answered by: Barbara Medford

QUESTION:

After this horrible drought, I am committed to xeriscaping with native Texas plants. The few hibiscus that survived have been transplanted into pots and are thriving. I bid the tiny boxwoods a fond farewell as I added them to the compost heap. (they had dried out so completely there was no sense potting them) My problem is with some Leucophyllum frutescens (Cenizo). I have planted a 10 of these gorgeous plants around my front yard in hopes of creating a hedge. A few weeks later, I ended up having to rethink this plan because of neighbors who don't curb their dogs. I decided to move them into a more organic grouping. The new arrangement is more haphazard, spacing varying from 2 feet to 4 feet. To keep the st. augustine from overtaking the patch, i covered the area in 1 layer of newspapers and then weed fabric and mulch. (overkill maybe?) The plants are approximately 18" to 24" in height at this time. While most of the plants are thriving, flowering and happy, the plants that were most exposed to urine and other insults are not flowering, their leaves turning a greyish brown and dropping. I suspect transplant shock. However, my sister mentioned that they were turning brown before the move. Could it be residual urine damage? What should I do?

ANSWER:

We think there is probably a set of circumstances causing you problems with your cenizos. First, however, we congratulate you on converting to xeriscape, removing the boxwood, which is probably either Buxus sempervirens, native to Europe, Western Asia and northern Europe or Buxus microphylla, Japanese boxwood. Neither belong in Houston. From an article by Virginia Cooperative Extension:

"Boxwood is not popular with everyone. In fact, some violently dislike it and refuse to have it on their premises. Those who do not like it may have had difficulties in growing it and have become disillusioned. Poor designs may also result from failure to properly maintain healthy, uniform plants." Box wood does best in moist soil and an environment free from extremes.

While we're talking about xeriscaping, aren't you getting tired of watering that St. Augustine grass? Not to get too much off the subject, we suggest your read our newly revised How-To Article on Native Lawns with Multi-Species.

Now, back to Leucophyllum frutescens (Cenizo). According to this USDA Plant Profile map, cenizo is endemic to Texas, mostly growing in west and south Texas. Obviously, it grows other places, including the Wildflower Center in Austin, but going to Houston is a stretch.

From our webpage on this plant (which read by following plant link above) here are the Growing Conditions for this plant:

"Water Use: Low
Light Requirement: Sun , Part Shade
Soil Moisture: Dry
Cold Tolerant: yes
Heat Tolerant: yes
Soil Description: Rocky, well-drained soils. Limestone-based, Sandy, Sandy Loam, Medium Loam, Clay Loam, Clay, Caliche type
Conditions Comments: According to legend, cenizo tends to bloom in conjunction with rainfall. Cenizo is easy to grow so long as it has good drainage. Though this species is the most irrigation-tolerant of the genus, it is susceptible to cotton root rot if soil does not have good drainage and remains moist. Humidity and high night temperatures are lethal. Cenizos should not be fertilized or over-watered. Drought- and heat-tolerant. During very cold winters, may lose a few leaves."

So, that's the "wrong place" part of our answer. Next, is "wrong time." Moving plants of any kind around in the Texas summer is always a bad idea. They are definitely a candidate for transplant shock, but the leaves may have already been browning by having been fertilized or over-watered.

But, to get back to your original question. Not being experts on doggy waste products, we found an article from The Daily Puppy, (no, honest) Male Dog Urine Effects on Plants. Sadly, in addition to the other environmental problems your location places on cenizos, this may be the last straw. But the dog problems will still exist if you totally replace the cenizo. There are probably NO plants that are going to be happy with continuing exposure. Here is that article's conclusion on Prevention.

"According to specialists, the best ways to protect plants or grass from an overdose of nitrogen and salt in dog urine is to immediately douse the area with water after a dog urinates. Flushing the area will wash the nitrogen and salts into surrounding ground, causing a neutralizing and dilution effect. Using a hose to wash away dog urine on plants will help prevent their leaves from browning."

That is a pretty big investment in time, attention and water. Possibly you have already attempted a little neighborhood intervention and found it ineffective. There are electric fences that supposedly will keep dogs inside their own area, but since you would have to leave a break in that fence to come and go, they could just come around and use the same break. We suggest that you contact the Harris County Public Health and Environmental Services, Veterinary Public Health Division, on the chance they will have some suggestions.

From the Image Gallery

Cenizo
Leucophyllum frutescens