FAQ #2

By Melanie Mathieson
Gardening Guru

•I planted some Lupin seeds that someone gave me last fall and none of them germinated. Why?
A: Lupin seeds have a very tough seed coat which needs to be scarified. Scarifying means to nick the seed coat with a knife, file with a nail file, or rub on sand paper to create a weak spot in the seed coat. Obvious great care must be taken when trying to nick or file these small seeds. Another solution is to soak the seeds in warm water over night before planting, similar to beans, peas and corn. Make sure the water is just warm as hot water will “cook” the inside of the seed.
•I have an established tree species that had dark burgundy leaves (Shubert chokecherry, red scarlet maple, barberry, purple rain birch) but they are turning green and are no longer burgundy. What is causing this?
A: There are a few possibilities that may be causing this. Any plant with coloured leaves has less chlorophyll in the leaves than if they were solid green. When a plant with coloured leaves starts to experience a stress such as drought, disease or pests the coloured leaves revert back to green to help the tree compensate for the stress it is under. I see this happen in many yards and gardens most often due to underwatering. Many gardeners underestimate the moisture needs of their trees and shrubs, thinking that a light rain shower is enough water. Trees and shrubs draw gallons of water from the soil per day, much of which evaporates into the atmosphere. Trees have extensive root systems in order to meet the demand for moisture. So make sure you provide ample water to your trees on a regular basis which may mean daily for newly planted trees and shrubs especially in the hot days in July and August. Other causes may include the wrong light situation (usually hybrids with coloured leaves prefer full to partial sun), too much moisture (sitting for prolonged periods in soggy soil), an insect infestation or a disease (i.e. black knot on a Shubert chokecherry that is cutting off the nutrients to the branches), or a recently fertilized lawn with a high nitrogen fertilizer.
•I have a plum tree that for many years has produced the best plums but this past season the plums looked fine then the next time I checked, the plums had blown up in size and looked like they were covered in black mould. What is this?
A: This is a sad situation because the plums are absolutely inedible and we all get lulled into the belief that our fruit trees will live and produce fruit forever. The sad reality is that tree like humans have a certain lifespan. When trees are coming towards the latter part of their lifespan, they begin to develop rot or diseases and sometimes both go hand in hand. Unfortunately the situation you describe is known as bladder plum, a disease that ruins the plums on a tree in the early growing stages. There is no cure for this disease although removing the infected plums from the ground in the fall and disposing of them in the garbage may help the next year. If the tree is quite old, bladder plum may just be a symptom of a dying tree. This is what I found on my plum trees when living in Fort Frances. The trees were about thirty years old and when I made the decision to cut them all down and replace them, they all had stages of rot in their lower trunks. If this is the first season your plum tree develops bladder plum, clean up all the leaves and infected plums off the ground and dispose of them in the garbage (do not compost them or use as a mulch), then wait until the next season to see what happens. If the bladder plum is present the next season I would recommend removing the tree. Wait a few years before replacing the old tree with another plum tree. Other fruit trees can be planted immediately as they are not affected by bladder plum.