Troubleshooting with Conway Lum

Credit: Barbra Fairclough

Rooting Around

When purchased in its original container, rooting hormone has an indefinite shelf life, but one should take steps to protect it from becoming contaminated. Plant cuttings, especially taken late in the season, inevitably become contaminated with fungal spores upon the arrival of moist weather. To use the rooting hormone, first transfer a small amount from the original container into a working container. Dip plant cuttings into the working container only, never into the original. Any excess rooting hormone should either be used up or discarded, not returned to its container.

Container Gardening 101

Repotting any container plant is easily accomplished by following a few guidelines. However, a big plant in a small pot doesn’t necessarily need repotting. To determine if a plant needs a new container, check the root ball’s condition; if the roots are a solid mass, then it is time to repot. Due to weight or size, it may not be possible to take a plant out of its container to inspect its roots. In these cases, try using a chopstick to see how easily it can penetrate the soil. Other reasons for repotting include when plants become top-heavy, when soil surface dries out faster between watering, when plants appear more lethargic or when roots are sticking out of the pot. Protruding roots, however, may not always be a reliable indicator, as shown by orchids. These types of plants dislike being disturbed when blossoming. Some flowering plants, including Hoya (wax plant), Hippeastrum (amaryllis) and orchids, prefer their roots to be cozy or root bound. The best time to repot is prior to active growth, early in the season or just after flowering. Foliage plants, such as palm, dracaenas and pines, can usually be repotted at any time of the year. In general, choose a new container one size larger than the previous one. For example, a plant in a 15-centimetre pot should be repotted to the next size up of 20 centimetres.

Moss on Tree Branches

I have a moss problem on the branches of my apple trees and would like to know how to get rid of this. – Dawn Dexter, Vancouver

Moss is usually not an indication of poor tree health, but it flourishes under conditions of excessive shade or poor air circulation. Thin out the affected trees no more than 20 per cent to improve light and air circulation. Moss can be removed physically by hand brushing, and/or by spraying lime sulphur during the dormant season – usually November to February. Always read the label for precautions before using any chemicals.

Tool Rules

It is amazing how gardeners ignore the importance of keeping pruning tools clean. I am sure the same individuals would never neglect to wash their own knives and forks at home. No matter how much money you spend on tools, they are only as good as your care of them, especially those expensive items. And yes, you still have to clean your tools, even if you plan to use them again the next day. Incorporating a habit of cleaning hand pruners, secateurs, loppers and knives can greatly extend their life expectancy. I find rubbing alcohol works quite effectively to remove excess plant sap and disinfect at the same time. A disinfectant solution can be made from either rubbing alcohol, bleach or Lysol, mixed with water at a rate of one to nine parts respectively. This solution can either be sprayed on or tools can be dipped into it between pruning cuts. This procedure will work also when cutting up potatoes, splitting orchids or dividing perennials for replanting. When dipping tools, make sure you change to a fresh disinfectant solution periodically. This will prevent the solution from building up as a contamination source to be redistributed again. Also keep in mind that bleach as a disinfectant can be harsh on metal tools. To prevent corrosion, make sure all tools are oiled down before storage.

Conway Lum is a Certified Horticultural Technician at Mandeville Garden Centre in Burnaby. Questions can be mailed to Conway at GardenWise, 4th Floor, 4180 Lougheed Highway, Burnaby, B.C. V5C 6A7, or emailed to