Hydrangea

Morning sun with afternoon shade is ideal; full sun can scorch leaves and dry soil too fast.

The genus's thirstiest group; never let it dry out fully in summer.

Moist, humus-rich soil that doesn't dry out. Flower colour on pink/blue varieties is genuinely governed by soil pH and aluminium availability, not fixed by variety alone.

Prune lightly in early spring, removing only old flowerheads back to the first strong bud pair, and remove one or two of the oldest stems at the base to renew the plant. Avoid hard pruning — it removes next year's flower buds.

A balanced general fertiliser and a mulch of leaf mould or compost as the buds break, then a high-potash feed in early summer. Avoid anything nitrogen-rich: it produces the lush green bush that never flowers.

Softwood cuttings from a non-flowering shoot in early summer are almost foolproof — trim below a leaf pair, halve the remaining leaves to cut water loss, and keep them shaded and humid.

More sun-tolerant than macrophylla.

Standard shrub watering.

Tolerates a wider range of soils than macrophylla, including drier and more alkaline conditions, provided it isn't waterlogged.

Prune hard in early spring, cutting all stems back to a low framework — flowers form on the current season's growth, the opposite logic to macrophylla.

Feed at the spring prune with a balanced fertiliser over a generous mulch, and again in early summer as the panicles build. This one flowers on new wood, so it can take a slightly more generous hand than macrophylla without going blind.

Softwood cuttings in early summer, or semi-ripe cuttings a little later; both root freely in gritty peat-free compost under cover.

Standard hydrangea siting.

Standard shrub watering.

Adaptable, moist but well-drained; more forgiving of poorer soil than macrophylla.

Prune hard in early spring like paniculata, cutting back to a low framework, since it also flowers on new growth.

One balanced feed with a thick mulch at the spring cut-back covers the year. Overfeeding is counterproductive here — the heavy heads already flop after rain, and soft, over-fed stems flop further.

Softwood cuttings in early summer root easily. The clump also suckers, so lifting and separating a rooted piece from the edge in spring gives an instant plant with no propagation kit at all.

One of the few reliable climbers for a north-facing wall.

Standard climber watering.

Moist, humus-rich soil; slow to establish, so improve soil well at planting.

Little pruning needed while young; once established, trim over-long shoots after flowering to keep it within bounds.

Slow to start and undemanding once away: a balanced feed and a mulch in spring is all it asks. A young plant that seems to sit still for two years is establishing roots, not asking for more fertiliser.

Layering is the natural method — the stems root where they lie against damp soil, so pin one down and sever it the following year. Semi-ripe cuttings are the alternative where nothing trails low enough.