AUTUMN time is feeding time in the plant world.

With citrus trees starting to develop fruit, now is a good time to apply plant food.

I have just given my potted lemon tree a mixture of, yes, Epsom salts plus a dressing of garden lime and Neutrog’s Seamungus (a certified organic combination of seaweed and chook poo). Actually, I also gave my roses the same mixture.

Many plants show signs of magnesium deficiency with yellowing leaves and just the deep-green veins showing, especially acid-loving plants such as Daphne odora, gardenias and the like.

The problem is easily corrected by dissolving a heaped tablespoonful of Epsom salts in a watering can of water and thoroughly soak the ground around the drip line of the bush.

One of Canberra’s great gardeners, the late Jim Macfarlane, gave me this advice about 40 years ago, saying he applied Epsom salts to every plant in the garden from conifers to azaleas. His spectacular garden in Griffith was a show stopper.

Bursts of hot daytime temperatures with cool nights, plus days on end of cool, rainy days have not helped. Perhaps it is going to be a great year for green-tomato chutney!

THE world-famous and historic Sydney Botanic Gardens comprise three gardens: the original Royal Botanic Gardens in the Domain, the Blue Mountains Botanic Gardens at Mt Tomah and The Australian Botanic Garden, at Mt Annan, which features only Australian plants, with 2000 varieties set in 416 hectares.

During the holidays we visited our favourite at Mt Tomah, a stunning cool-climate garden, the highlight of the Botanists Way, the historic crossing through the dramatic northern Blue Mountain World Heritage Park on the Bell’s Line of Road at Bilpin.

The plants are arranged geographically to showcase Australian and exotic cool-climate plants from around the world.

Formal gardens, including rose gardens, herb gardens, displays of perennial plants with the dahlia display (which will present a kaleidoscope of colour this autumn), separated by neat, trimmed hedges surround the visitors’ centre and restaurant.

The picnic area is hugely popular at weekends as is the café with its wide verandas and spectacular views across the mountains. The formal areas gradually change to informal plantings down the hillside.

A new feature at the gardens is The Bower. Taking the theme of the satin bower birds that collect everything “blue”, the gardens have interpreted the specialised stick structure the male bower bird constructs to entice the female. It is constructed of willow, an environmental weed the Lithgow Council allowed the gardens to collect along creek banks. Apple tree prunings from the famous Bilpin orchards have also been woven into the structure.

All three gardens are open every day except Christmas Day and Good Friday. Entry is free.

• Ensure you have stakes in place with dahlias, being careful not to put the stake through the tuber.
• Spring bulbs can be planted any time now in a sunny spot. With a few exceptions, they do not like shade at all. If you have bulbs in shady places due to trees or shrubs growing, now is the time to dig them up and replant in a sunnier place.
• Broad beans and radish seed can be sown now as well as transplanting seedlings of leek and English spinach.