Heather (Erica): can it be revitalized when old and woody

(Question)

Hello,
I recently moved to a new home in Niagara peninsula. The soil is heavy clay, but the gardens have been conditioned with top soil (many years ago). There is a plot of heather (Erica) blooming now (mid April), but only about 15% is blooming. The rest is quite purple brown and woody and not blooming at all. Is there any way to revitalize it? I know i cannot over prune it. If it’s no longer green, does that mean that given it’s brown and woody, and not blooming, those portions of the plot need to be replaced? Or is there any other solution you can offer me to revitalize the plot?

(Answer)

Thank you for contacting the Toronto Master Gardeners with your query concerning your heather.

In general all true heathers are cultivars of just one species, Calluna vulgaris (which sometimes get classified as Erica vulgar. The true heaths belong to the Erica genus  and include more than 700 species. Both heaths and heathers are members of  the Ericaceae family.

Spring Heath (Erica carnea) is a low growing plant (20cm) native to the alps flowering in April/early May as soon as the snow melts It comes in Red, Light pink and white flowers; it requires acidic and sandy soil (well drained) and full sun.

Scotch Heather (Calluna vulgaris) is also a low growing plant (25cm) native to Scotland and flowers from August to October. It comes in purple, pink, crimson and white flowers; it also requires acidic and sandy soil (well drained) and full sun.

The biggest enemy for heather is extreme cold (-6C or lower). The best way to protect your plants from the extreme cold and fluctuations in temperatures is snow. Problems occur when the period of deepest snow does not overlap with the periods of deepest frosts.

The following is taken from the North American Heather Society’s bulletin Heather News #58, Spring issue ’92.

http://www.heathsandheathers.com/care/page5.html

Winter.  Clearly the lower the temperature, the greater the potential for plant damage. However, it’s not that simple.  An extreme low temperature in January is not nearly as likely to cause damage as one in November when the ripening of the wood has not reached its maximum. Drops in temperature of a short duration are not as likely to cause problems as those which last an extended period  Perhaps the most critical factor is the earliness and depth of the snow cover.  Even if the air temperature is -25 degrees F it will be a balmy +25 degrees F under two feet of snow.  By applying pine needles or evergreen boughs it is often possible to raise the snow level and help bring plants through difficult winters. 

When to prune a plant depends on when it blooms and whether the flower buds are produced on old wood,( last seasons growth) or on the current season growth referred to as new wood. I mention this because depending on which genus of heather you have determines the proper time to prune. From your description it appears that you have Spring Heath, Erica carnea. Since this plant flowers in April/May it should be pruned after flowering. Pruning later in the season will remove next year’s flower buds.

To check if you plant is viable, simple scrap away some of the bark with your fingernail. If the wood under the bark is green then your plant is still alive. If this is too difficult to see you can break off a stem of the heather. If the stem is pliable and the inside of the stem is green or white and soft, the heather is alive. If the stem is brittle and easily breaks in half, the heather might be dead. When pruning heather remember to stay in the green. Do not go down into the brown woody area – it might not regenerate new growth, for more info see Pruning & Cuture

For more information on Heathers please see the following links:

How to grown Heathers and Heath, The Heather

Good Luck with your Heather