FAQs about shrubs

By Melanie Mathieson
Gardening Guru

A former column talked about what to look for in deciding on the ideal shrub for your landscape design. Once you have the shrub(s) planted, like many gardeners you may have a question concerning a specific problem. Here are some frequently asked questions and answers, for your information.
My shrub was growing fine and then all of sudden the leaves wilted and turned brown, what happened?
This can happen often with shrubs. In the Rainy River District in the summer of 2010, it has probably happened due to an over abundance of rain. Check to see if the ground is remaining soggy for long periods of time where this shrub is planted. If so, you may need to dig the shrub up and add some fine gravel to the planting hole to ensure adequate drainage. Be careful though, as this was an exceptional year for rainfall and next year could easily have drought conditions. Now the opposite thing happened to two of my shrubs in Thunder Bay this past summer. Two lilacs have died completely due to drought. Even though they were watered on a regular basis, the heat and lack of rain this summer was just too much for them. I will dig them up next spring and replace them with a new shrub.
I purchased a dwarf variety shrub a few years ago and it hasn’t grown at all, why?
It may appear that this shrub hasn’t grown at all but it has, all be it a very small amount. Most draft species are hybridized to grow to and maintain a very reduced size in comparison to the full size variety. As a result, annual growth on these type of species is very small (around a centimeter or so) so it is very hard to detect. As long as your tree is healthy and maintaining its annual colour you have nothing to worry about. If you want a bigger shrub, you may have to choose a different variety and move this one to another spot. Note the slow growth rate also applies to many of the species that have been hybridized to maintain certain shapes.
I would like to plant some shrubs but my soil is very poor. How do I correct this?
Many other columns have stressed the importance of good soil nutrients and condition. But to make a long story short you need to add some organic matter such as compost, peat moss or well rotted manure. Check to see what soil requirements are needed for the species of shrub you want to grow and adjust your organic matter accordingly. For example, rhododendrons, azaleas, junipers like acidic soil so add more peat moss. Blend the organic matter into the soil well and then follow the instructions for proper planting techniques from a previous column.
The leaves of my shrub looked bleached out, why?
Excessive sunlight can scorch leaves on shrubs, especially when they are a type of shrub that prefers a low light location. If this is the case, it is best to relocate the shrub if it is not too big, to a shadier location. Scorching can also occur on shrubs growing in a shady location that are suddenly exposed to full sunlight (i.e. a larger tree is cut down, the shrub was relocated, buildings or fencing is removed, etc., causing a change in the light conditions). Scorching can also occur when hot, dry winds are prevalent during the summer months. These types of winds cause the surface area of the leaves to dry out and the root system is not capable of replacing the moisture to the leaves fast enough, so scorching results. The leaves may appear bleached out, or are dry and withered. This can be prevented in the future by ensuring that during dry and hot conditions, that the tree/shrub receives plenty of water and the roots have ample space to grow.
I had planted a shrub with burgundy leaves, now they are green. What happened?
This is a classic case of insufficient moisture. When a tree or shrub has coloured or variegated leaves there is less chlorophyll in each leaf. When it comes under stress, usually by not receiving enough water, it must convert its coloured leaves back to green in order to produce enough chlorophyll to keep itself alive. Increased watering will usually solve this problem. The best option is not to allow this to happen in the first place as this process causes undo stress on the tree or shrub, making it more susceptible to insect and disease infestations in addition to drought.