GET PLANTING
Unless you’re in a sheltered area of Britain, grow the agave in a container and move it undercover for winter. The planting will do best in a sunny site with well-drained soil. Clear the area thoroughly, breaking up compacted ground and working in well-rotted organic matter. After planting, mulch the area with more organic matter to reduce weeds and conserve water.
1 Pot up the agave
Buy your agave in spring or summer. Choose a container that’s only a little bigger than its current pot . Ensure it has drainage holes and fill with a loam-based compost with at least a third added grit for good drainage and some controlled-release fertiliser. Plant at the same depth it had been growing, water in and finish with a gravel mulch. Move the plant outside once all risk of frost has passed. Water only when the compost dries out during the growing season, then slow up in autumn and keep dry from October through to spring. Move back into a greenhouse before the frosts and cover with fleece in severe weather. Alternatively overwinter in a conservatory but water occasionally in warmer temperatures.
2 Plant the saponaria
This perennial needs an ‘approach with care’ label, as it can be invasive. If you’re worried, swap ‘Rosea Plena’ for Saponaria lempergii ‘Max Frei’ or to a pink-flowered phlox such as Phlox paniculata ‘Franz Schubert’. Plant the saponaria in spring or autumn. They don’t need any support and their romantic softness is a great counterpoint to the agave’s spikes. They will spread once established and clumps can be lifted and divided in autumn or spring.
3 Add the acanthus
Acanthus are deep-rooted plants that establish best if planted young. Look out for new plants in spring, or beg a friend to split a clump from their own garden. When dividing mature clumps be aware that acanthus propagates readily from root cuttings, and that it’s difficult to move plants without leaving fragments of root in place. Some people view bear’s breeches as
tricky to eradicate so it’s worth getting the planting spot right first time.
4 Plant the melianthus
This dramatic shrub is best planted in spring; if you plant in autumn they can struggle to get established before the onset of freezing weather. Improve the planting spot by adding extra well-rotted organic matter. Try to ensure the spot is protected from cold winds. In early winter cover plants with a dry mulch for protection and leave in place until spring. Then prune back hard just before new growth begins.