Glory days

Late summer flowering flowers are at their peak in August with dahlias and tender perennials such as cannas producing their wonderfully rich blooms that glow, jewel-like in the gradually lowering sun.

The daisy-like blooms of Rudbeckia are also in full swing on plants two metres or more high at the back of the border or much smaller, 50cm or so, at the front.

One of the tallest is Rudbeckia laciniata, which can get up to 2.2m/7ft high with large bright yellow daisy-like flowers and a green cone. The slender stems sometimes need staking, especially in an exposed site, but are worth this little effort since the flowers last from July to September and are great for the middle or back of a border.

The variety Rudbeckia laciniata Goldquelle' flowers for a similar period, but only grows to about 39ins/1m high with double yellow blooms 8cm/3ins or across.

Other popular perennial Rudbeckias include Goldsturm', 70cm/28ins tall with black-centred deep yellow flowers and dark green foliage. It is very long flowering, especially in good moist soil and will bloom from June until October given the right conditions.

Herbstsonne' has rich yellow flowers topping stems up to 2.3m/7ft tall, while Rudbeckia occidentalis Green Wizard' is more unusual, with green sepals instead of yellow petals, surrounding the large central black cone.

The rudbeckia family doesn't just include perennial plants, the species Rudbeckia hirta and its varieties is an annual. Like the perennials, most are yellow-flowered but they don't grow as tall, with Gloriosa Daisy' being among the tallest, reaching 90cm/36ins high.

The late flowering blooms of this plant are large, 17.5cm/7ins across in shades of yellow, orange and red. Kelvedon Star' grows to a similar height with smaller bright yellow flowers marked with deep brown at the base of each petal, while Green Eyes' has pointed yellow petals circling an olive green cone.

Cherokee Sunset' has more unusual double chrysanthemum-like blooms in shades of warm yellow, orange, bronze and dark brown. It is a strong, sturdy plant that looks particularly good planted in a group to show off the range of colours in the flowers. Quite different to the tall airy Rudbeckia lacinata.

Rudbeckias are generally easy to look after, although the perennials can be attacked by slugs and snails as they start their growth in early spring. Any reasonable soil will do for this family as long as it doesn't dry out in summer, and both annual and perennial species will grow in full sun or semi-shade.

Perennials can be divided in autumn or spring while annuals need to be sown in gentle heat in late winter or early spring depending on the variety. They then need to be planted out in May or after the last frosts have passed.

Weekend catch up

Deadhead dahlias to keep the plant producing new flowers and not wasting its energy on producing seed. The spent flowers can be nipped off by hand but this tends to leave unsightly stems so it is better to use secateurs and take the whole flower stalk back to where it joins the main stem.

This job is not likely to be one I will be doing this year as my dahlias have been very disappointing with only one out of four plants producing any flowers at all and even then we have only had two. There are plenty of leaves and stems but no flower buds forming. Has anyone else had this problem?

Gardening TV and radio

Sunday, August 27

2pm, R4, Gardeners' Question Time. John Cushine, Bob Flowerdew and Anne Swithbank answer questions from gardeners in Merseyside.

Bank Holiday Monday

6.30pm, Channel 5, Nice House, Shame About The Garden. A concrete garden in Borehamwood is turned into a Mediterranean paradise.

Tuesday

6.30pm, Channel 5, Nice House, Shame About The Garden. An overgrown garden in Bromsgrove, Worcestershire.

Wednesday

6.30pm, Channel 5, Nice House, Shame About The Garden. Creating a relaxing beach-style area.

Thursday

6.30pm, Channel 5, Nice House, Shame About The Garden. A garden makeover in Chessington, Surrey.

Friday

8.30pm, BBC2, Gardeners' World. New series. How has drought affected the garden? From vegetable gardens to herbaceous borders, the team give their top tips for saving parched plants.

Open Gardens

Sunday

In aid of St John Ambulance.

Ness Hall, Nunnington, six miles east of Helmsley, off the B1257 Malton-Helmsley road. An old walled garden with herbaceous plants, orchard, new borders, woodland area and fruit and vegetable gardens. Admission £3.50 adult, 50p child over 5 years old. Open 2pm-5pm.

In aid of the National Gardens Scheme. Cruckhouse Farm, Lower Norwood Road, Norwood, six miles west of Harrogate. Tranquil garden on the slopes of the Washburn Valley with flower borders, pool, jungle water garden, herb knot, potager, orchard with woodland beds and long shrub borders leading to walks around wildlife ponds within a setting of meadows and farmland. Open 2pm-5pm. Admission £2.50.

Londesborough Cross, Shiptonthorpe, off the A1079 York-Hull road. A former railway goods yard transformed into a garden with ponds, bog area, large herbaceous borders, screes, rock garden and a woodland garden planted with a large collection of ferns and other shade loving specimens. Open 1pm-5pm. Admission £3. Also open Wednesday.

Wednesday

In aid of the National Gardens Scheme. Hunmanby Grange, Wold Newton, 12.5 miles south-east of Scarborough on the road from Burton Fleming to Fordon. A three-acre garden created from an exposed field with fences and hedges providing shelter for a series of gardens planted for year-round colour and interest with seasonal highlights.

Open 1pm-5pm. Admission £2.50.

Londesborough Cross, details above.