Want To Grow the Forbidden Plants???

San Antonio Express News
Sunday, February 27, 2005

By Dr. Jerry Parsons

Everyone wants to grow plants that are “special” and require extraordinary care and planning to have them survive and/or fruit. People from the southeastern U.S. want their azaleas, blueberries, dogwoods and pine trees. People from the northern states want their lilacs, peonies and cherries. People from the subtropical areas of the U.S. want their citrus, pineapples and flowering tropical plants. Horticulturists might as well be whistling into the wind as trying to tell these folks they can’t grow these plants in this area. The soils are alkaline here versus acidic where blueberries, azaleas and pines are grown. It doesn’t get cold enough in the winters here to grow lilacs, peonies and cherries. It often gets too cold in the winters here to grow most citrus, pineapples and flowering tropical plants.


These determined people will spend any amount of money and die trying to “do what everyone says can’t be done!”

I have been dealing with this mentality for 30 years here in San Antonio. Age and experience has taught me that you cannot reason with a determined gardener, so you might as well try to help them achieve their goals of growing plants which cannot be easily grown here.

Let us begin with our friends from the southeastern U.S. since, being from Tennessee, I am included in this group. We are going to have our azaleas and blueberries!!! What we have to do is create a micro-environment of soil which favors these acid-loving plants. We have to eliminate the native soils which have alkaline parent material. Alkaline plant material is practically impossible to change to acidic and even more difficult to maintain in an acidic condition. So to grow our acid-loving plants in this alkaline environment, we must create an acidic growing media which can substitute for soil and will maintain its acidic nature as decomposition occurs. The only way to accomplish this is to use organic materials produced in environments which are totally acidic in nature and eliminate possible leaching and de-acidification of the root zone of the acid-loving plants to be grown.

Growing plants in large containers is the best solution. A soil-less peat base mix which drains rapidly should be used. Ideally, when you pour water around the plant, water should soon be coming out of the bottom of the container. This not only indicates proper drainage but also enables leaching of fertilizer salts which, if accumulated, can damage a plant’s root system. Soil-less mixes should be soil-less– absolutely no alkaline-based soil! Many suitable types of soil-less peat base mixes are commercially available. A soil-less peat base mix should be disease and weed free, retain adequate moisture after watering yet is well drained and lightweight. Essentially you will have created an “acid bog” with peat base potting mix to assure good growth. Be sure to incorporate a slow release fertilizer such as Osmocote into the peat base potting mix . Avoid the use of rapid release, nitrate fertilizer and use an acid based, water soluble fertilizer once a month during the growing season after the plants are established. Then you can grow the azaleas and blueberries of your dreams.

For pines in this area, use alkaline tolerant replacements in the conifer family that survive our soil and weather such as Italian stone pine, Japanese black pine, Aleppo pine, Deodora cedar, Arizona cypress, bald cypress, Montezuma cypress and several junipers (cedars). Afghan (Mondale or Eldarica pine) will only survive in a well drained site for 10 to 15 years and is not recommended for most of Texas. For dogwoods, visit the San Antonio Botanical Garden in early April to see their beautiful dogwood and azaleas in all of their glory.

For people from the northern states who want their lilacs, peonies and cherries-I can’t help you very much. Our winters are simply not cold enough, our summers are too hot, and we have too many diseases. I can suggest a lilac substitute in the form of a fragrant, alkaline-loving, deer-resistant plant which has blooms like a lilac but bigger named ‘Texas Lilac’ Vitex. It will be available in nurseries this spring.

And finally, for people from the subtropical areas of the U.S. who want their citrus, pineapples and flowering tropical plants, Texas A&M horticulturists to the rescue!! A complete write-up about growing patio citrus in Texas landscapes has just been launched at: http://aggie horticulture.tamu.edu/patiocitrus/. Pineapples and flowering tropical plants will have to be grown as annuals or protected from temperatures below 35 degrees F.

If you are willing to make some environmental modifications and plant substitutions, you can grow what some consider the forbidden fruit and flowers of South central Texas. As any self-respecting, obstinate gardener knows, the doing what they say can’t be done, makes the fruit oh, so much sweeter and the flowers oh, so much more precious.

This article was written by Dr. Jerry Parsons, Extension Horticulturist (Vegetables) with Texas Cooperative Extension in Bexar County.

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