Ensure heather stays healthy with pruning after blooming
Q I have a problem with pruning the large heather plants in my garden. They really need to be cut back severely, but when I cut back into old wood that part of the plant dies. Sometimes the entire plant expires. How can I avoid harming the plants when I prune, and is there a preferred time of year or method for reducing the size of heathers?
A: Heathers are kept as compact and neat as possible by cutting them back after flowering every year, from the time the plants are young. It is most common to remove just the faded blooms, but as much as half the length of flowered stems can be removed.
Even with yearly post-bloom pruning, eventually some of the plants will become woody and straggly beyond redemption. Then, it is best to dig them out, renovate the soil, and replace them with young transplants. The ones that settle in most easily and flourish best in my garden are very young heathers, purchased in 10-centimetre wide pots. Q One of my water-saving routines is to use dishwashing water on garden plants. Now I’m wondering whether this might be unwise. Can dish detergent harm flowers and vegetable plants?
A: That depends on the product you use, its dilution rate, and the amount of greasy material left in the used water. Some detergents are more caustic than others. The safest ones will note on their labels that the product is certified as biodegradable and that the contents include no toxic solvents. Most supermarkets stock environmentally benign cleaning products, and almost all health food stores sell them.
Dish water is most safely used on well established plants such as shrubs, trees, and hefty food plants like rhubarb rather than on annual flowers and vegetable plantings. I’d avoid its use especially on leafy greens.