Monday, February 26, 2024

Fertilizer and variegation

Question:  I purchased ‘Rob’s Whippoorwill’, which originally had variegation on the outermost ring of leaves, but it has now started to turn all green.  I feed all of my violets with ‘Miracle-Gro African Violet Food’ (7-7-7 formula), every time I water, 10 drops per quart.  Am I feeding too heavily for a variegate?  Do they require more or less light than the average violet?  This is my first try with variegates, and I’m not happy with the results.  Am I doing something wrong?

Answer:  Not necessarily.  To begin with, ‘Rob’s Whippoorwill’ is a Champion (or crown) variegated variety that can easily lose its variegation with age.  In this case, it’s probably the variety, not you, that’s the source of your frustration.  In explaining further, we’re about to say a few things that will fly in the face of conventional wisdom.

Beyond the habits of the variety itself, our personal experience tells us that the single, most important, factor in determining the amount of variegation is temperature.  Variegation is always greater when plants are grown in a cooler environment.  Variegates can be sensitive to overfeeding, especially since heavily variegated varieties seem more likely to show signs of fertilizer burn on leaf margins and tips.  It’s also true that, because of the lesser amount of chlorophyll in their leaves, they grow slower and process relatively less food than do all-green varieties.  Still, feeding them significantly less, or feeding them low-nitrogen fertilizers, won’t necessarily produce heavier variegation–it just means that the green portions of the foliage will be a lighter shade of green.  We feed our variegates the same balanced fertilizer as all of our other violets, since our goal is a plant whose leaves have green portions that are dark green, and whose variegated portions are bright white (or yellow, beige, etc.).  Conventional wisdom also says that variegates require less light.  We suppose, in theory, that they do.  But in practice, we’ve grown them precisely the same as all of our other violets with no noticeable difference.

If you really want to grow heavily variegated varieties, simply grow them in as cool an environment as possible.  By cool, we mean night temperatures as low as 60-65f degrees, and day temperatures less than 70-75f degrees.  For those varieties whose foliage tends to turn green with age even when grown in moderate temperatures, here’s a trick we use for growing showplants.  Remove all but the center row or two of foliage, and remove all but a third of the root system.  By “starting over” these all-green variegates, the new growth (assuming, again, that your conditions aren’t too warm) should be variegated, at least long enough to show.  For those not growing for show, is it really that important?  After all, are the blooms on an all-green “variegated” plant any less pretty than those on a non-variegated variety?

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