Each week, Susan Richards of New North Greenhouses answers your gardening questions. Have questions about your gardening needs? Please email her at email@example.com.
Jackie: I have found a few leaves on my Pinky Winky hydrangea turning yellow. Some have dark spots on them. I keep pulling the yellow leaves off whenever I find them. Is this a disease or pest? Will this destroy the plant? What can I do for this?
If they are yellow with no sign of chew holes the problem most likely isn’t an insect. If it’s the oldest leaves, then it's most likely stress of some kind – either under watering or over watering.
If the problem is throughout the shrub, then you may have a fungal or bacterial leaf spot happening. You can treat this by spraying with the a copper sulphate-based fungicide. This will help prevent the spread of the disease.
Also remove any diseased leaves as soon as you see them and discard in the garbage, not the compost pile.
When watering, try to keep foliage dry, delivering water to the root area of the shrub instead.
Beth: My husband is concerned about the back lawn. Whatever this is has invaded the grass and is taking over a large patch. Do you know what this is? And do you have a solution to get rid of it?
Beth that weed is Creeping Charlie, Glechoma hederacea. Unfortunately it is very hard to control. Don't hoe this weed as little bits left in the soil will start a new plant. Rotor tilling is even worse as you are breaking the plants up into MANY pieces! Unfortunately this plant also spreads by seed.
The best non-chemical control is to pull it out with a straight rake or weeding tool, but don't expect to eradicate it in one season. Diligence is the key. However, if a neighbour leaves it unchecked, the seeds can reestablish the plant.
You could try a weed killing product that targets broadleaf weeds in the lawn. Several applications will be needed.
Creeping Charlie thrives in the shade, so if this is a shady area, do you have the option of thinning the tree canopy to let in more light?
Also, keep the lawn nice and healthy so it has a chance to crowd out weeds.
Bonnie: Is there anything that I can spray on the flowers and potato vines in my flower pots to keep away the ants and earwigs. They are getting holes all over them. I tried putting ant powder around the pots, and they just kept eating away. Now the earwigs are starting too. I purchased Safers' spray for flowers etc. I sprayed it on my Engelmann Ivy for the aphids, but not sure about my flower baskets and the ants and earwigs.
Any insecticide spray has to hit the insects to be effective. Earwigs hide during the day and feed at night. If you lift the pots and find an earwig colony there, have an insecticide spray handy to use right away.