Greenland prides itself on knowledge as well as customer service. Here is some helpful advice on growing tender roses in Alberta.
Download a pdf of Growing Tender Roses or view information below.
Plant in an area with at least 6 hours of continuous sunshine and good air circulation. Soil should be deep, well drained loam, rich in organic matter at a pH of 6-7.
The planting hole should be twice as wide as the root ball and 6 - 8 inches deeper than the graft or branching terminal. Water all transplants well. Water soluble transplant fertilizer should be used to encourage rooting (10-52-10 or Later’s Root Booster). Pruning at planting time should be limited to removal of broken or damaged branches.
In a rich fertile soil, only an annual spring application of fertilizer is needed. In poor soil, 2-3 feedings from late spring to mid July may be applied. Use fertilizers specifically formulated for roses to ensure adequate micronutrients are available for healthy growth.
The best time to prune tender roses is when new growth has begun. In Alberta, mid to late May is ideal. Prune to remove dead or damaged canes and to shape the plant. Flower production can be stimulated with proper pruning. Removing fading blossoms helps ensure a continuous supply of blooms during the summer.
Shrub roses can be trimmed to 6-7 main stems. Pruning cuts should be made 1/4” above the bud eye, at a 45º angle, sloping away and down from the bud. Always cut to an outside leaf which contains 5 leaflets.
Roses are tolerant to dry periods once established however during dry spells, deep watering about once a week is required. Roses require 5 gallons of water per week. Avoid wetting the leaves or splashing soil on them . Watering in the morning gives the leaves a chance to dry preventing any problems with diseases. Roses do not compete well with weeds. Herbicides should not be applied during the first year. Mulches can be an effective weed barrier and conserve soil moisture at the same time.
Pests and Diseases
Aphids are sometimes a bother and insecticide may be required. An all-purpose spray or rose dust may be applied according to directions. Powdery mildew can be controlled by spraying 1.5 tbsp of baking soda to 1L of water.
Winter Care of Hybrid Tea Roses
Before placing mounds of protection around your roses there are a few things that need to be done first. Clean around the bushes, taking care to get all the dead leaves etc. as these can be sources of fungal disease.
Remove broken or dead canes. Give your roses a final soaking of water, this should be done several days before the ground freezes. Materials to use for mounding are well pulverized dry soil, shredded bark mulch, dry peat moss, dry sawdust, or dry straw. Snow also makes an excellent insulator and can be piled up around the mound later. It is not a good idea to use fresh leaves as these might be damp and can cause the mound to be soggy and end up rotting some of the canes.
Heap the material you are using for your mound at least 2 feet high, shake the branches of the rose bush to ensure that the material has settled down around the bush and that there are no empty air pockets for cold air to be trapped.
Be careful not to remove the protective covering too soon in the spring, this could cause the rose to die from spring-kill. Wait until other trees in your yard are starting to bud before uncovering. Remove the protection gradually, one layer at a time. Keep something handy to cover in the event of frost or late snowfall.
During extremely cold winters, canes may freeze and die back to the snow line. In the spring the dead wood should be removed and maintenance pruning practices should be followed.