Expert Advice

Category: Fertilizing

Question: I put my shrubs in last year, what should I fertilize them with this spring?

Answer: It is a good idea to use a root start fertilizer for the first fertilizing after the plants first winter. This will help repair any root damage suffered from the cold temperatures and help the plant roots grab hold. Use a liquid fertilizer such as Transplanter, Root Booster or Miracle Gro Quick Start. Wait until the ground warms thoroughly before applying.

Category: Fertilizing

Question: I love my new Endless Summer hydrangea. How do I make sure that it always blooms blue?

Answer: Lowering the pH of the soil will produce blue flowers (pH 5.2-5.5)as it aids in the absorption of aluminum. Using aluminum sulphate will do the trick. Follow the instructions on the package. Adding organic mater such as peat moss or pine needles every year will also help.

Category: Plant Information

Question: How early can I plant in spring?

Answer: Be cautious planting too early in spring as we usually will have freezing nights until late May. To avoid damage from frost, either delay planting, have a protected area to store new plant purchases or be prepared to cover new plants especially if they have leafed out. Be patient and your new plants will reward you with great growth. Avoid fertilization until the ground temperature rises (usually after the 3rd week of may). Happy plants are counting on us for wise care.

Category: Plant Information

Question:  I saw a plant in a neighbor’s yard and I’d like to know what it is. I saw it in May and it was a low carpet of very bright pink flowers and the leaves looked almost like short spruce needles.

Answer:  Most likely what you saw was a type of creeping phlox. The common types are moss phlox, Arctic Phlox or douglasii phlox. They are all sturdy low growers which are a solid mass of bright blooms in the early spring. All are hardy for the Edmonton climate.

Category: Plant Information

Question: Can we plant apple trees in late summer or early fall or should we wait until spring?

Answer: Planting apple trees is a great early fall project. Plants root heavily in the fall and do not have the hot summer days to contend with or the stress of rooting and producing leaves at the same time as in spring.

Category: Plant Information

Question: I have a small front yard and I want a tree that flowers but produces little-to-no fruit. Are there any options?

Answer: Yes, there certainly are some options. A very popular tree which flowers but produces no fruit is the Spring Snow Crabapple. It is a small, sterile tree which has white flowers in spring, a round, compact canopy and yellow fall colour. Another option is Starlite Crabapple. This too is a small tree with white flowers in spring and produces tiny red berries later in the season which are retained on the tree once the leaves fall off. The red berries offer a striking contrast in winter and they become a food source for birds.

Category: Plant Information

Question: We purchased a bunch of trees and shrubs this year and it will be their first winter in the ground. Is there anything I need to do to help my plants survive?

Answer:  Yes there is. The most important thing is to make sure all your plants are moist when the ground begins to freeze in early November. This is especially important for evergreens. With cedar or upright juniper, give them a spray of Cloud Cover or Wilt-Pruf late in fall and again if we warm up in February to reduce the amount of moisture they lose. Snow cover any tender or low shrubs.

Category: Plant Information

Question:  It’s October and my Evan’s cherry tree still has green leaves. What should I do in order to get it to go into dormancy. What happens if you cut the green leaves off? Would it help?

Answer:  Even though the leaves are still green the tree should be dormant. Cutting the leaves off isn’t necessary though it would do no damage. Check for buds that have been set for next years leaves. These appear like bumps in the V between the branch and the leaf stem. If these are there the tree should be fine. To encourage slow down and dormancy start holding back the water in September. Don’t let it go bone dry but stretch out the time between waterings. Also, make sure not to fertilize them after about mid July to allow time for them to absorb it, grow and slow down in preparation for winter.

Category: Plant Information

Question:  When and how do I transplant raspberries?

Answer:  If you’re digging fresh canes do it first thing in spring before they leaf out. Select only the greener one year canes for replanting. Remember that raspberries are best in sunny well-drained spots. Space them about 24″ apart to allow them to expand as new canes emerge. Cut the newly planted canes down to about 10″ directly after planting and water them well. Also apply a root start fertilizer 3 times about 10 days apart. Potted raspberries can be planted any time during the growing season.

Category: Pests and Diseases

Question:  The leaves of my tree are very shiny and there are wasps all around it. What’s causing this?

Answer:  Most likely the cause is small soft bodied insects called aphids that attach to the back side of the leaves. The aphids release a sticky slightly sweet substance called honeydew that the wasps are attracted to. To reduce aphid numbers you can rinse the plant off with a jet of water or spray with an insecticidal soap solution. Trounce is another product that is stronger than soap but still safe to use and is highly effective against aphids. Be sure to read product labels carefully and follow the directions when applying any spray to your plant.

Category: Pests and Diseases

Question:  The top of my spruce trees are brown and it looks like the needles are gone. What could have caused this?

Answer:  It sounds like yellow-headed spruce sawfly. Did you happen to notice any yellowish-green caterpillars with darker heads? These little critters eat the needles especially near the top. The adult sawfies come up from the soil in late May to mid June and lay eggs at the base of new needles. The caterpillars hatch out and feed until about mid-July. They then drop to the ground and form cocoons in the soil and the cycle continues next year. Spray with Malathion or Permethrin when the caterpillars are actively feeding as the insecticide needs to come in contact with them to kill. Occasionally working up the top two inches of soil under the spruce may also help by disturbing the cocoons. If left untreated for a few years the sawflies can kill the tree.

Category: Pests and Diseases

Question: I have an eating apple tree and the apples are brown inside and not usable. What is causing this?

Answer:This most likely is a pest called Apple Maggot. In mid-to-late June the adult Apple Maggot flies emerge from the soil in the drop zone of infested apple trees where they have overwintered. Adult flies usually travel less than 300 metres looking for a host tree where the female deposits eggs under the skin of immature apples. The eggs hatch into tiny caterpillars which spend the summer chewing away inside the apple. In the fall when the ripe fruit drops to the ground, the larvae exit the fruit and enter into the soil where they form a cocoon that survives the cold winter temperatures and they then pupate into a fly. Spraying an insecticide is ineffective but there are ways to control the fly population. In June and July when the adults are flying, hanging several sticky traps that mimic ripe apples in the tree can help control the population as the flies are drawn to these traps. These traps can be purchased at most garden centres. Also, in fall, pick up and throw away any apples within a day or two after they drop. One can also place an impermeable barrier such as landscape cloth under the drop zone of the tree to catch the apples and prevent the larvae from entering the soil to overwinter. These insects can also attack plum, cherry, pear and Hawthorn trees.

Category: Pests and Diseases

Question: The leaves on my Swedish Aspen are rolled into tight little tubes but when I open them up there is just little black bits inside. What’s causing this?

Answer:  These are called leaf rollers. They don’t really cause the tree any problem, the damage is primarily cosmetic. A little green caterpillar rolls the leaves, chews a little and eventually drops down to the ground. The black bits are just what the caterpillar leaves behind. The next stage in the life cylcle happens in the top couple of inches of soil so fluffing up the soil around the trees from time to time will help reduce numbers.Once the leaves are rolled there is no way to contact or kill the bugs with any pesticide. There is a natural predator of these leaf rollers and by not spraying hopefully their numbers will increase to the point they will keep the leaf roller in check.

Category: Pests and Diseases

Question:  Some of the leaves on my Swedish Aspen turn a reddish-brown colour mid-summer. What is causing this?
Answer:  This sounds like Bronze Leaf Disease (BLD) and it is a fungal disease that has started to appear in the Edmonton area. The symptom first appears on the leaves (the colouring of them) with the fungus then moving into the branch resulting in dieback. Infected leaves will remain on the tree throughout winter. Trees susceptible to this disease can decline and die after being infected for several seasons. The disease spreads by airborne spores and this happens in spring once daily temperatures average 18 degrees Celsius. So far there are no known chemical controls for BLD so early detection and good sanitation practices are key to help stop the spread of the disease. Diseased branches should be pruned out below the lowest visable point of infection and be either burned or buried. Trees severely infected or ones that have recently died from BLD should be removed and either burned or buried. Maintaining good plant health with adequate water and fertilizer will help trees to stave off this disease.

Category: Picking Plants

Question:  I need a tough drought resistant hedge for a rental property which will be dense enough to deter dogs but not grow much taller than about 4 feet.

Answer:  Pygmy caragana make a great small dense hedge. Once established they are drought resistant and tough. Unlike the more common hedge caragana they are easily trimmed to about 4’ and do not set large volumes of seed.

Category: Picking Plants

Question:  We are planning to create a hedge of Boxwood around our corner property. It will be maintained at a 3′ height. I need to stop people from crossing out yard. What variety would you suggest?

Answer:  Unfortunately, Boxwood would not be the best candidate for what you are looking for. It is really not dependable enough for our zone to be practical as a hedge. A few possible substitutions would be Pygmy Caragana, Emerald Carousel Barberry, Cotoneaster, Alpine Currant, and Prairie Joy Rose to name a few.

Category: Picking Plants

Question: We are looking for a feature tree for a front yard with limited space. We are hoping to find something that will hang, bloom and not get over 6′ tall! Not sure if there is such a thing.

Answer: It does exist! The Royal Beauty Crab sounds like it should fit the bill. It is a weeping crabapple with deep-pink flowers which turn into deep-red coloured fruit. It can be pruned to maintain an umbrella shape.

Category: Picking Plants

Question: We have a low area in our yard which can get quite wet. What types of plants can we put there?

Answer:  Most trees and shrubs prefer moist, well-drained locations. There are some trees and shrubs which will take wetter locations (not standing water though). The best bet for a wet location would be a Willow. Willow trees (Laurel Leaf, Golden, Prairie Cascade) will be fast growing and get large so they are not a good choice for smaller yards. Dwarf Arctic Willow and Blue Fox Willow are two shrubs that would be a good choice for a wetter location.

Category: Picking Plants

Question: I have a small front yard and I want a small tree that flowers but produces little or no fruit. Are there any options?

Answer: Yes, there certainly are some options. A very popular tree which flowers but produces no fruit is the Spring Snow Crabapple. It is a small, sterile tree which has white flowers in spring, a round, compact canopy and yellow fall colour. Another option is Starlite Crabapple. This too is a smaller tree with white flowers in spring and produces tiny red berries later in the season which are retained on the tree once the leaves fall off. The red berries offer a striking contrast in winter and they become a food source for birds.

Category: Pruning

Question:  When is the right time to prune my apple tree?

Answer:  If a heavy pruning is needed it is best to prune your apple tree in late spring (late March thru early May). At this time the temperatures are warm enough for healing to occur but the tree is not yet in active growth. Light pruning can be done either in spring or after mid September. The time to avoid pruning of any tree is July and August. Pruning can cause a growth response in the tree and you do not want to stimulate a late flush of growth that doesn’t have enough time to harden off before freeze up. Clean your pruning tools between cuts on your apple tree with a 10% bleach solution to stop any transfer of disease.

Category: Pruning

Question:  I want to trim back my Brandon Elm and raise the head a little. When is the best time to do it?

Answer:  Elm is a special case because of the measures that need to be taken to reduce any possible spread of dutch elm disease. Because of the Dutch Elm Disease risk, there is a pruning ban on elm between April 1st and September 30th. Pruning on either end of this period is fine. Remove all dead branches that you see.

Category: Pruning

Question:  I have a birch and a maple in my yard that I would like to prune. When is the best time to do this?

Answer: Always prune Birch and Maple trees when they are in full leaf. Ideally, these trees should be pruned in July.

Category: Pruning

Question:  I have many evergreens that need to be pruned in my yard. When should I do this?

Answer:  Most evergreens generally need little pruning. Most dwarf, mounding and columnar evergreens can be lightly sheared with a clean, sharp set of pruners or hedge shears to accentuate the shape. Clip off about 1/3 of the new growth in mid-June for a bushier shrub. This will allow new buds to form after shearing and ensure that there is an even flush the following year. Cedars and junipers can also be cut back by 1/4 to 1/3 of the new growth after it has emerged and before it has started to harden and mature in mid to late summer.