Shoots that revert to solid green, such as on this Elaeagnus pungens 'Maculata', should be cut away soon after they appear.

Are Your Variegated Plants Reverting?

by Ron Knight
Images © Ron Knight

I like variagated plants. Their yellow, cream, or white streaks and blotches brighten up shaded areas and provide interesting contrasts in my garden.

However, most of them have a major problem. They occasionally produce a shoot that has lost its variegation and reverted to solid green. Some of the main offenders in my garden are Rhododendron ponticum 'Variegatum', Hydrangea macrophylla 'Maculata', Euonymus fortunei 'Emerald 'n' Gold', and Elaeagnus pungens 'Maculata'.

The reverted shoot on this Hydrangea macrophylla 'Maculata' is more vigorous than the shoots with variegated leaves.

What causes variegation? It involves some complex genetics, but generally, a mutation in leaf cells results in the green chlorophyll being masked or absent. Chlorophyll going missing is not a happy event from the plant's point of view since the pigment is needed to trap light energy that is used to manufacture food. That's why variegated plants are often not as vigorous as their solid green progenitors.

Commercial growers produce variegated plants by taking cuttings from shoots where variegation has occurred. The cloned shoot is called a "sport". Apparently, all variegated plants are field tested before being brought to market in order to select those that are least likely to show reversion. Still, in my garden, almost every variegated shrub has produced a pure green shoot from time to time.

The genetics that produce variegation on plants like this Rhododendron ponticum 'Variegatum' are little understood.

In my rhododendron patch, the variegated inmates are President Roosevelt, R. ponticum 'Variegatum', and Goldflimmer. Of the three, the variegation in Goldflimmer is by far the most stable. The other two, every year or so, produce shoots that have mutated back to a solid green.

The cure for reverted foliage is simple; prune out the entire shoot that holds the solid green leaves. Otherwise, since the reverted foliage is often more vigorous than the variegated foliage, it can eventually grow to dominate the plant and ruin its appearance. The variegated hydrangea in the photograph above provides a good example. The pure green leaves are larger than the variegated ones and the reverted shoot grew much taller than two other shoots which originated at the same point on a main branch.

As you do your gardening chores, look closely and you may be surprised, as I was, to see how many of your variegated plants are showing reversion. Then, get out your pruners and perform a bit of corrective surgery.

Ron Knight is a retired biology teacher, past-president of the Vancouver Rhododendron Society, and a confirmed rhodoholic. Ron and his wife Carla are the creators of Caron Gardens where they display over 450 different rhododendrons and companion perennial plants in a natural woodland setting on Hotel Lake. They also sell award-winning rhododendrons and use their garden and classroom to offer workshops which are advertised in the Pender Harbour Community School newsletter and the SCRD magazine. Detailed information on several upcoming workshops is available online. You can contact Ron at 604-883-9807 or by e-mail at carongardens@telus.net.