I’ve been giving my ceanothus a haircut this week, as it’s trained against a fence and needs an annual prune to keep it tidy.
Wall-training shrubs which are otherwise inclined to get a bit big and unwieldy is a great way to keep them in bounds. Ceanothus is a good candidate, and so is Japanese quince (Chaenomeles japonica), pyracantha and Garrya elliptica. The small-leaved cotoneaster, C. horizontalis, holds itself so rigid it practically stands up against a wall by itself, without supports.
The principle is pretty straightforward: you’ll need supports, such as wires spaced about a foot to 18″ apart, to train the shrub onto before you start.
Then, year by year, you shape the shrub so it’s flat against the wall. You do this just after flowering: just prune out any branches growing out away from the wall completely or, if you’re at risk of ending up with bare stems, you can prune back to one or two leaf joints from the stem.
Tie in side shoots pointing the way you want them to go, and then trim any upward-growing stems to about an inch (2.5cm) below the top of the fence or wall. If any longer side shoots are growing beyond the bounds you want them to keep to, shorten them, too.
Pyracantha in particular makes a really lovely espalier if you do this: ceanothus is a bit more bushy, so you get a pleasing evergreen “coat” to disguise your fence with. In any case, you avoid the problem you get with climbers where they’re forever climbing next door, or over the neighbouring shrubs; and it looks great, too.