May

Helianthus ‘Vanilla Ice’ is one of the prettiest sunflowers varieties available. With clusters of delicate pale creamy-yellow flowers with dark chocolate centres this compact variety grows to just 120 to 150cm (4 to 5ft) tall is suitable for the border or can be left add a naturalised charm to a wildlife friendly garden.

Perennial sunflowers typically don’t grow quite as tall and large as their annual friends. However Helianthus maximiliani is a wonderful exception. It grows slowly through the summer months as a group of short stems, until late summer when the stems bolt and the flowers head for the sky.

Most gardeners are familiar with the annual sunflower, however, it is the perennial varieties that coexist most happily with other garden plants. Helianthus mollis is a lovely perennial with butter-yellow flowers. It grows 120cm tall and requires little more attention than an annual cutting to the ground.

From the Tian Shan Mountains of northern China comes this tough little subshrub that is among the finest expressions of silver foliage to be found. Helichrysum thianshanicum is a superb silver leaved evergreen, subshrub that forms a tight mound of eye-catching silver foliage.

Heliopsis ‘Summer Nights' is a special selection made by Dale Hendricks of North Creek Nurseries, USA. Introduced in 2004 it produces a profusion of single blooms in early to mid-summer, with rich, deep golden-yellow petals and deep mahogany centres. The foliage is red-tinted and the stems are tinted dark burgundy.

Herniaria glabra is a relatively unknown perennial that deserves to be used more often in our gardens. The nursery industry calls it ‘Green Carpet’ and well they should. This lovely bright green creeper spreads effortlessly in all directions. An excellent choice for between flagstones or as a lawn substitute.

Gorgeously scented pure white flowers are held above rosettes of dark green leaves. Like all sweet rockets it is highly attractive to bees and other beneficial insects, the fragrant flowers perfume the air in late spring and early summer evenings. The night-scented stock is a close relative.

Dames Rocket produce flowers varying in colour from deep rich purple, through all the paler lilac shades to white. Highly attractive to bees and other beneficial insects, the fragrant flowers perfume the air in late spring and early summer evenings.

Dames Rocket was the favorite flower of Marie Antoinette. The genus name Hesperis is Greek for evening, a reference to this plant's aroma becoming ever more conspicuous towards evening. The fragrance is as sweet as a violet's. The night-scented stock is a close relative.

Hosta are grown predominantly for their outstanding foliage, from leaves as small as a teaspoon up to those larger than a dinner plate, colours range from deep blues to silvers, darkest shiny greens to bright yellows, from a single solid hue to the myriad of variegations the choice is almost overwhelming.

Hyssopus officinalis 'Alba' is a much less well known variety of hyssop. Also known as 'White Hyssop' the plants sport bright white flowers from July to October. Widely used as a 'taste enhancing' herb or wildlife plant, the plants are a dark, vibrant green with a spiky, upright habit and narrow tongue-like leaves which have a peppery scent when stroked.

Hyssop, once recognised as a medicinal herb is enjoying a revival with home gardeners. An aromatic herb similar to rosemary or lavender, it makes an excellent low hedge and more unusual alternative to box. The plants are a dark, vibrant green with a spiky, upright habit and narrow tongue-like leaves. 'Pink' Hyssop sports vibrant, pink flowers.

Hyssop is a strong-flavoured aromatic herb which is enjoying a revival with home gardeners. An ideal plant for use in containers or as a low hedge or border within the herb garden. Highly attractive to bees, it makes excellent honey and is a must for any wildflower garden.

An extremely easy to grow, hardy annual plant, Iberis umbellata is quick to grow and is in bloom within two months from a spring sowing. This beautiful lilac form has glossy green leaves and the familiar clusters of fragrant flowers which are attractive to bees, butterflies and other pollinating insects.

Iberis umbellata 'Rose-Cardinal' is quick to grow and is in bloom within two months from a spring sowing. Extremely easy to grow, they are invaluable for underplanting and for use in rock gardens and containers. They are considered one of the best plants grown for edging purposes.

Iberis umbellata is a popular and easily-grown annual plant that is perhaps more versatile than you might imagine. Considered one of the best for edging purposes, they are also invaluable for underplanting, for rock gardens and containers. Easy to grow and fast to flower, this fragrant hardy annual will quickly cover any unsightly bare spots in the garden.

Throughout the summer, large, pure white flowers of Ipomoea alba open quickly at night, releasing sweet perfume into the evening air. Position near to your patio where you can enjoy the fragrant scent in the evening. A wonderful plant for a moth, night, or fragrance garden, the large white blooms appear to illuminate the garden

This heirloom morning glory originated in Bavaria in Germany and named for the original Seed-saver Baptist John Ott, Ipomoea purpurea 'Grandpa Ott' flowers of intense violet-blue, with a ruby red star. It is a good climber for walls, trellis work or if allowed to scramble through other plants or trees.