As you can see, the surface of their compost had become covered with moss, which is often a sign of general malaise. Furthermore, the plants didn't put up any new basal shoots last year, so I think their compost may have run out of nutrients. The time to re-pot them had definitely come.
I thought that getting the plants out of the old pots might be quite tricky, but as it happened it was very straightforward because the rootballs were very tightly packed and smooth. They just slipped out of the pots when I pulled on the stems.
Before putting the plants in their new pots, I used an old knife to roughen up the rootballs and tease out some of the main roots so that they will more easily be able to explore their new compost.
The old pots were 10" / 25cm diameter round ones, and the new ones are 15" / 35cm square ones, so considerably bigger.
Blueberries need acid soil, so I used this "Ericaceous compost".
I placed a thick layer of compost in the pot, put the plant in, and backfilled all round it with more compost, pushing it in fairly firmly to make sure there were no air pockets. I also added a handful of Blood, Fish and Bone meal to give the plants a real boost.
I'm hoping that with this treatment the Blueberries will put on a lot of new growth this year, because their fruit is borne on the previous year's wood. If no new wood forms in one year there will be very little fruit the next year.
I am planning to give the same treatment to the two remaining mature plants, but I'll need to buy some more compost before I can do it. This plant is my best one. It has plenty of branches, but just look at the moss!
This year I'm hoping for a good crop of Blueberries, and because I recently bought all those new aluminum rods I will be able to avoid having to rely on a Heath Robinson style fruit cage like I hurriedly constructed last year. This is the sort of harvest I want (several times over, preferably):
