Fern Alder and Heidi Harvey: Kent CaCO3

Giving plenty of vigorous growth, this clematis has star-like, creamy white flowers from midsummer to mid-autumn. Give it space to spread, ideally into trees or up against a large wall where it'll need close-spaced horizontal wires or trellis to snake through. Like all clematis, it likes having its roots in the shade and its head in the sun, and being planted with the top of the roots 8cm underground. On planting, cut back to 20cm above ground, above a pair of buds. Thereafter, give an early spring prune, again 20cm above ground. It has been given the Award of Garden Merit by the RHS.

The big advantage of growing 'Plena', and not its much bigger species parent, is that it has double white flowers, and makes a fantastic show in May when it's in full bloom. Give it a prominent position, in the middle of a lawn (but note it will eventually get very big) where it can be clearly seen. There's another good show in the autumn when the dark green leaves colour up before falling. It has been given the Award of Garden Merit by the RHS.

Anybody who has been on holiday to the Canary Islands will have probably noticed the flower-heads of this plant growing out of the lush undergrowth. Echium pininana is a stunning plant for any sheltered border providing a tropical touch to the summer. In its first year echium forms a low rosette of silver, hairy, spear-like leaves. The following year it suddenly spurts into growth and produces a single 4m (13.1ft) high flower spike festooned with blue, funnel-shaped flowers. After flowering the plant dies, but not before scattering its seeds. In mild parts of the UK these may germinate where they land, but in colder areas seeds should be sown under glass in spring. Plants flower every second year, so sow seeds every year to ensure a continuous supply of blooms.

The loosestrife is a tall wildflower that grows by streams and natural ponds. It has strong, upright stems, this hybrid being topped in summer with long, poker-like heads of purple-pink flowers. They do not need staking but, because plants can be vigorous, they need dividing every few years to stop them getting out of control. Grow with other moisture-loving plants in damp, boggy ground. Beware slugs, which love the new shoots.

One of Chris Baines' favourite wildflowers, teasels make fine, architectural plants in the garden. Spiny flower-heads rise out of the prickly rosette of leaves in summer. These are covered in pinkish purple or white flowers in mid- to late summer. They then dry to an attractive shade of brown and make fine dried flowers for arrangements. Teseals are biennials so they need to be sown in late spring where they are to flower the following year. Beware that once they are established them will self-seed freely.