Is there a way to differentiate perennial from annual hydrangeas? I’m never sure what I’m buying and have been told I’m buying the perennial version only for them not to come back after the winter. I live in Zone 5 in Toronto’s Bluffs neighbourhood.
There is no difference: all hydrangea are woody perennials.They are bush plants known for their large clusters of flowers in a wide range of colours. Old hydrangeas were not very cold tolerant but new varieties grow well in cold climates, especially if you are in Zone 5 as you state. They do need some pruning: remove approximately one third of the older stems each year to maintain optimal flowers in the spring.
Hydrangea can handle sun and may wilt slightly mid day in full sun but will revive with moisture and evening. When planting use a slow release fertilizer with a NPK ratio of 10-30-10, water well and top dress with compost. The ideal soil type is loam; if you have sandy soil, peat moss can help absorb moisture. Soil should also have at least 5% organic matter. Your planting hole should be slightly larger than the pot size. If the roots are tightly packed, loosen them gently before planting to encourage root growth. The crown of the plant (where the base of the stems meets the soil) should be even with the ground level. If the hydrangeas is placed too high it can easily dry out, if placed too low, it can cause the hydrangea not to bloom and potentially rot. Hydrangea prefer well drained moist soil, and a layer of mulch can help conserve water and keep the ground cool.In winter you need to protect the potential buds on the old wood.
If you have followed these steps and have purchased a good quality plant, your hydrangeas should grow. If you purchased from a reputable nursery there may be the option to take your plant back and get a replacement depending on the vendor’s policies.
The following site gives you many of the same details as above but with graphics that make it much easier to follow. Good luck.