PLANT YOUR BORDER
Start with a weed-free site. Dig out any weeds, break up compacted ground and add plenty of well-rotted organic matter across the area. If you discover perennial weeds, consider thoroughly cleaning the site by mulching them into submission this summer with a thick barrier before planting next spring. If your soil’s on the heavier side, add some gravel as well as well-rotted organic matter to lighten it and improve drainage, especially if you intend growing the bearded iris.
1 Establish the rose
Container roses can be established at any time as long as you keep new plants watered during dry spells. Plant bareroot roses when dormant from late autumn to early spring. Prepare a generous planting hole and mix in extra well-rotted organic matter, with a sprinkling of mycorrhizal fungi to help establishment. Water container-grown plants thoroughly at least an hour before planting and briefly soak bareroot roses in a bucket of water. Position the rose with best face forward, making sure it’s at the same depth as it was growing previously. Backfill firmly, water well and finish with a mulch of wellrotted organic matter. Deadhead right through the growing season to keep the display coming.
2 Plant the iris
It’s best to plant container-grown bearded iris from June until early autumn. Find plants the sunniest space in the border and ensure the soil’s well-drained. Plant at the same depth as they were in the pot, or plant bare root irises as soon as you receive them, so the rhizome sits just on the soil surface. Cut the foliage back by a third to reduce wind rock while the plant gets established. Remove stems after flowering and tidy away dying leaves in autumn. Divide established clumps every three to four years after flowering. Lift the clump, snap off the outer healthy rhizomes and replant these youngsters.
3 Bring in the nassella
Airy Mexican feather grass is another plant preferring good drainage and a bit of elbow room. Position one or two within reach at the front of the border for a stroke as you walk past. They’re best planted from mid-spring to early summer so look out for containergrown plants now. Nassella tenuissima isn’t the most longlived perennial but it self-seeds and can be divided in late spring. Comb through clumps in March to remove old leaves and stems.
4 Add the persicaria
This delightfully robust plant copes with most soils, but to get the best display make sure it doesn’t dry out over summer. Establish new plants in autumn or early spring, finishing with a mulch to help conserve water. Water occasionally but deeply during dry spells. Deadhead after flowering and divide large clumps every three years in early spring.
5 Sow the foxglove and sweet rocket
Sow biennial foxgloves and sweet rocket from late spring to midsummer, to flower the following year. You can sow direct into a seed bed for transplanting later, or under cover in seed trays to prick out and pot on before planting out in autumn. Deadhead sweet rocket to keep the flowers coming and cut back the main foxglove stems as they go over to encourage smaller secondary flowers. Deadheading both plants prevents excessive self-seeding but leave a couple to ensure the next generation of seedlings. Some may turn into shortlived perennials and flower the next year.
6 Sow the flax
Linum perenne is a semi-evergreen perennial that loves hot, dry, well-drained conditions and dislikes root disturbance. Sow seed direct into a gritty soil April-June where you want it to flower. Sow generously because these slender plants require large numbers to make an impression.