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Monday - November 05, 2012

From: Blanco, TX
Region: Southwest
Topic: Diseases and Disorders, Soils, Vines
Title: Chlorosis in Texas Wisteria from Blanco TX
Answered by: Barbara Medford

QUESTION:

Just noticed a Texas Wisteria I bought last month and it is already looking chlorotic. Mixed compost in w/the dirt it is planted in but I don't think that will be enough. Is Blanco soil too alkaline? Any soil organic ammendments I could use to acidify after it's planted?

ANSWER:

As you can see from this USDA Plant Profile Map, Wisteria frutescens (American wisteria) occurs naturally in Texas only in counties in far eastern Texas. As do all wisterias, it requires an acidic soil, which of course you don't have in Blanco County. The compost was a good step, as that will aid in drainage. Poor drainage can often contribute to chlorosis.

Please read this previous Mr.Smarty Plants answer which deals with chlorosis, in this case, Sophora secundiflora (Texas mountain laurel). We are wondering if what you have diagnosed as chlorosis might be something else altogether. The wisteria is deciduous, it may just be preparing to go dormant for the winter. You just planted it, so it could very well be suffering from transplant shock. If you follow this plant link, Wisteria frutescens (American wisteria), to our webpage on that plant, you will see this in Conditions Comments:

"Conditions Comments: Prefers a good loamy soil in a sunny south or southwest facing position, sheltered from cold winds and from early morning sun on frosty mornings. Plants can become chlorotic on alkaline soils. Prefers a rich soil, but some gardeners feel too rich a soil results in too much leaf growth. Tolerates seasonal flooding."

We already know you have an alkaline soil and probably clay; you can't change that. Otherwise, consider what growing conditions you have given your plant and compare with those on the webpage for that plant. If you decide you have positioned the plant in the wrong place, it is still early enough to transplant it. It can be trimmed back for transplant, and if you repeat the addition of compost, plus some supplemental iron to the soil, you may very likely be able to have a flourishing vine next season. Our webpage also says that the vine can do well in a circumneutral soil, which is to say it doesn't absolutely require acidity to survive. One of our favorite gardening quotations is that plants don't necessarily grow where it is ideal but where they can get away with it. We think, with a little tweaking, your wisteria should be able to get away with it.

From the Image Gallery

American wisteria
Wisteria frutescens