Several of our trees have ‘burnt leaves’. It looks as if someone has put a match under them ie 1 our cornus, our tricoloured beech, a lady Di clematis, and an elm(young). Also our fringe tree,(weeping wisteria) looks like its leaves are drying up. All these plants are in different gardens in our yard, with diff light, but mostly sun. None of our acers appear affected. Thank you.
Sorry to hear your beautiful collection of trees and shrubs are showing signs of stress. The challenge is to determine what is the cause of the symptoms you describe and these could be due to a number of factors or even a combination of more than one.
The symptoms you describe could also be leaf scorch. This is a non infectious physiological condition caused by unfavourable environmental conditions. Scorch damage alone is insufficient to kill an otherwise healthy plant. Proper treatment depends on the reason for scorch symptoms; however good cultural practices that improve general plant health and promote good root growth will reduce the chances of leaf scorch. The mention of unfavourable environmental conditions could include a lack of water, food, extremes of weather or other environmental conditions for good growth. It could be a nutritional deficiency or it could be a disease/virus (for example fungal disease can make their presence felt in humid conditions).
Often leaves looking dead or brown at the tips may indicate a potassium deficiency, too much boron, too much fluoridated water, or the weather is too cold or too hot (for example unseasonable weather patterns are a frequent cause of disorders so if these symptoms occurred after the very humid spell of weather that may have been a factor), or the plants have become too dry.
Steps you can take to help at this time are to prune all the dead foliage. Burn these, do not dispose in your compost if you have one and cut a minimum of 24″ (60cm) below the affected/ infected area. Take care to keep your garden tools disinfected before and after this pruning. Add organic matter around the base of (but not actually touching) your trees and shrubs and water well (ideally using rain water and ideally in the early morning).
You could do a soil test (you can purchase simple soil testing kits at any garden centre or big box store and the Ontario Ministry of Agriculture and Rural Affairs (OMAFRA) has a list of accredited soil testing sources on their website: omafra.gov.on.ca/english/crops/resource/soillabs.htm
This may help you determine if the soil has any nutrient deficiencies.
You could also seek help from an aborist which could be well worth the cost with that many trees affected. If you want to follow this route you can find an arborist in your area through the Landscape Ontario site: