It used to be that spring and summer were the best seasons for gardening, but with climate change and a rise in summer temps, the autumn garden has come into its own.
The heat stress of summer is over, which means that plants need less water but still grow and flower happily. By including autumn flowering perennials your garden can look gorgeous through to winter.
The rich purple or blue flowers of salvia contrast beautifully with the gold, red and orange of the changing leaves. Add splashes of golden yellow with gaillardia or coreopsis, or bring in the butterflies with white flowering gaura, euphorbia and scabiosa. This is also the flowering season for pelargoniums, from the tumbling ivy leaf varieties to the shrubby regal pelargoniums.
What’s to like about perennials?
- Perennials are less demanding than annuals. They last longer, are easier to grow and are more value for money as one gets more than one season out of the plant.
- Because of their stronger root system, most perennials are generally more drought and heat tolerant. All they need is regular watering and fertiliser once a month during their growing season.
- Most perennials grow happily for four to five years, even longer, in the same place before they need to be divided.
Pick of the purples
Purple is a lovely colour to use in the garden. It adds depth, especially when complemented by other flowers or foliage in shades of yellow, orange and green. It also blends with white or pink blooms.
Salvia ‘Mysty’ is a compact border salvia with purple-blue flowers and dark green leaves. Plants grow 30 – 46cm high and wide. They flower from late spring through autumn, producing many flower spikes. It is one of the most heat and drought tolerant of salvias.
Salvia ‘Purple and Bloom’ is a variation of the strong growing, ‘Black and Bloom’. It grows 1.2m high and wide, and is able to handle heat, humidity, and drought. Deadheading is not necessary although pinching off spent blooms produces a bushier plant. Plants flower until the first frost.
Verbena ‘Cadet’ Violet is an upright growing verbena for pots or garden beds. It reblooms so quickly that plants don’t appear to cycle in and out of flushes. Plant in sun or semi-shade or provide plenty of morning sun but afternoon shade for plants in containers.
Go for gold
Gaillardia ‘Mesa’ is an improved version of the traditional gaillardia, producing more flowers from spring to autumn on more upright, well branched plants that do not ‘flop over’. It grows 40 -50cm high, has nonfading intensely yellow flowers that are produced in its first year.
Coreopsis has sunny yellow flowers and blooms reliably in its first year. It grows in full sun, and is a compact, upright plant with a height and spread of 60cm. Coreopsis ‘Double the Sun’ has semi-double golden flowers and ‘Uptick’ has bicolour blooms in gold and bronze or yellow and red. Plant in soil that drains well.
White and bright
Gaura ‘Belleza’ is a naturally compact variety that grows upright with dense spikes of flowers that hold for longer. Plant en masse for an airy border or hedge or mix with other plants. It is always showy and just keeps on flowering. It can be cut back in early winter, if or when it stops flowering.
Scabiosa ‘Flutter’ is a pure white variety that produces a mass of flowers through to the end of autumn. It is neat and compact, growing 30cm high and wide. The large flowers are carried on sturdy short stems and are a magnet for butterflies and bees. Plants are hardy and disease resistant.
Euphorbia ‘Breathless’ is an excellent bed filler staying compact at 40cm but with a 60cm spread. It provides a mist of tiny white flowers from spring through to winter, when it dies down but comes back in spring. It grows best in full sun and needs little care.
A royal flush
Regal pelargoniums flower best in spring and autumn but will flower through winter too if sheltered from cold weather and receive plenty of sun.
‘Novita’ is upright growing and shrubby, with small, serrated leaves and an abundance of medium-sized flowers in vivid colours; purple, red, violet, dark red with a purple eye, and a pink bicolour. The plant is dense and compact. Plant in well drained fertile soil and let the soil slightly dry out before watering. It is also a good container plant. Trim bushes to retain their neat shape.
How to get the best from your perennials
- Because perennials remain in the same soil for about four to five years, they need a good foundation. Prepare the soil well, adding plenty of organic matter, compost, bonemeal and a general fertiliser (organic if possible) and dig it over deeply.
- Water regularly and fertilise in spring and midsummer.
- After flowering, cut stems down to the ground. This encourages new growth and in some cases a new flush of flowers.
- Mulch with a thick layer of compost because this continues to feed the soil and keeps the roots cool.
- The appearance of smaller and fewer flowers is usually the signal to divide. The best time to divide is after they have flowered.
Article supplied by Alice Coetzee