"I have yellow stuff dropping all over my car, my tiled deck, my kitchen skylight and my white siding. It doesn't wipe off and has to be removed with a scrubbing brush. This has been going on a few months and I can't keep on top of the cleaning. The environmental department at City Hall reckoned it was bee droppings, but there are hardly any bees here. What I can't understand is that my neighbour hardly has any at all."

Joadey Caldwell

via e-mail

This problem happens when aphids infest the trees and excrete a sticky substance that falls to the ground. There's probably an aphid-filled tree close to your house and parking spot. Your neighbour doesn't have the same trouble because the offending tree is outside your house, not hers.

Locally, I've come across this as a problem mainly on birches and lirodendrons (tulip trees) -- but any tree badly infested with aphids creates a similar situation.

If the tree is not enormously tall, you could try blasting the aphids with water from a hose. Once they've fallen out of the tree they don't usually climb back again.

Ladybugs, lacewings and parasitic wasps all feed on aphids, but sometimes an infestation is too massive for natural predators to make a difference. There are organic sprays against aphids in garden centres, but spraying even a small tree would be hugely expensive and you might have to do it more than once. I'm sure a jet of water is the best solution if you tackle this yourself.

"We replanted our own raspberry bed last year and enjoyed great berries last year. This year the berries are extremely small. I suspect lack of water is the cause. When is the critical time to ensure enough water for maximum size berries? Any other ideas for a miserable crop?"

Nancy McAskill

via e-mail

It's very likely lack of water is the cause -- and if you have water restrictions, you'll need to make decisions about which plants can wait a few days for water and what can't.

The critical time for watering any food crop is when the crop starts to form. With raspberries, this is immediately after little green berries start appearing. Then water either every day or as often as you can until the crop is harvested. After that the raspberry plants can be allowed to get somewhat dry, though not to the point they wilt.

Manure or compost helps to produce fat berries, but for moisture retention I've found grass clipping mulch a huge help. Two or three inches (five to eight cm) each year works for me. Water doesn't evaporate fast because the soil is covered. Some gardeners dry clippings first before spreading them and pull back the mulch slightly from stems aiming to prevent fungal disease or rotting. This is helpful for some plants, but I've not found it necessary for raspberries. Besides holding in moisture, fresh grass clippings deter weeds. But if you have weedy grass, you'll have a few extra weeds popping up next spring.

Raspberries can get viral diseases that make berries small. But since you had a good crop last year I'd advise you to try mulching first.

- Anne Marrison is happy to answer garden questions. Send them to her via amarrison@shaw.ca.