Did you know your lovely hydrangea’s great, great, great grandmother was brought into this country from Japan in 1790?
It is surprising how many people have a hydrangea in their garden and it’s possibly because they thrive on neglect and flower from June right up to autumn. Even during the winter the brown heads remain.
I am writing about hydrangeas this week because I have had several letters asking about pruning and why they change colour.
Hydrangeas are not fussy about the soil. They prefer moisture and don’t look good during droughts, but if the ground is chalky, the flowers are normally pink. Even reds, whites and blues change to pink.
It is possible to achieve blue heads by using hydrangea colourant which comes in tins at garden centres. Simply follow the directions.
Another idea is to use rusty iron just below the surface of the soil. When I was an apprentice at Southsea rock gardens there was a hydrangea growing 10 feet away from a dripping old iron hydrant, the heads turned from pink to an amazing blue after only about three months.
Pruning is best done after flowering. On huge overgrown specimens it is a good idea to look at the base of the shrub to find a short shoot and to then cut a huge branch out right down to the base of the shrub. This is repeated so about one in three branches is removed completely. The little buds will grow, replacing those which were removed.
On smaller specimens pruning is best done in the spring. Simply remove any dead wood and the dead heads.
At the tip of most of the branches a plump, pointed bud will be seen. This bud will produce the flowers during the summer.
Some people cut the hydrangea right down to ground level during the autumn to give the garden a good clear-up. The new shoots will grow like mad but there will be no flowers. Very disappointing, and lots of husbands upset their wives when they do the end-of-season clear-up. But the good news is that the flowers will appear the following summer, so eventually all is forgiven.
What about feeding?
This is best done in April. Fork down a couple of inches under the canopy of the plant and add 4oz of Vitax Q4 pelleted fertiliser scattered where the ground was forked and lightly fork again.
Water. This will ensure the long-lasting fertiliser will become active.
Keep the ground moist to ensure great heads of flowers. They aren’t really flowers but we won’t go into that now!
TIP OF THE WEEK
Remove single flowers on begonias which should have double flowers. If you forget to do this even more single flowers will appear.