Gardening Articles by Russell Fransham

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H. tiliaceus


Psyche


Swan Lake


Fantasia


Lady Cilento


Tango

Hibiscus

This article first appeared in Subtropicals magazine Autumn 2004

Hibiscus are such blatant tarty things and seem to go in and out of fashion so often, but I love them anyway. I guess I'm just that sort of boy. But there are a few tricks worth knowing about how to keep them looking good.

  • Firstly, they must have loose friable soil with lots of air in it to get them through Winter without root-rot. Clay is OK only if its well worked up as if you were planting lettuces or carrots. A foliar spray of Foli-R-Fos in Autumn always helps ward off the dreaded rot.
  • And secondly, they need hard pruning just like roses in late Winter, say July or August. At this time they also need a hefty feed of sheep or chicken manure and again about Christmas time. Remember that flowers only grow on new growth so the more old growth you cut off the more flowers you'll get. Just don't leave it too late in Spring as you'll delay the onset of flowering.

Of course they vary hugely in size and hardiness so some are much more clay tolerant than others.

Of particular interest are some of the species Hibiscus. Here are some of my current favourites.

Hibiscus schizopetalus is a vigorous African species with tiny delicate dangly flowers where the petals are so divided that they look like orange lace. This is also called the 'Coral Hibiscus' and the 'Spider Hibiscus'. While fast-growing and tall, this one is also quite frost-tender and benefits from severe pruning every year or two.

H. arnottianus 'Wilder's White' is from Hawaii with lightly fragrant white flowers with a red stigma. This one is a small hardy, coastal tree with rounded leathery leaves, often red-margined. The flowers start in February and tend to appear across the top of the tree, often too high up to see them well.

And if you've ever sat under the trees on the beach in Bali, you probably sat under

Hibiscus tiliaceus, the coast Hibiscus, which is actually native throughout the tropics in coastal areas including brackish swamps on the edge of estuaries such as Pearl Harbour and the mangrove forests of the Daintree river. It has heart-shaped leaves and lemon yellow trumpet-shaped flowers with a dark maroon eye that turn orange before they fall. This is a small shapely tree to 5m in NZ but reaches 25 metres in the tropics. In Samoa it is known as 'Whau', probably because of the similarity to the unrelated NZ species, and the lightness of the wood which is widely used for carving. In the Daintree river they grow right in the water with long beards of white roots from the submerged branches trailing in the current.

Of the hybrids perhaps my favourite Hibiscus is 'Psyche', the dangly scarlet flower worn in people's hair throughout the Pacific. It is the most widely planted ornamental Hibiscus in the world and I'm not even sure that it's a hybrid. I suspect it could be the original H. rosa-sinensis but its origins are lost in antiquity. Its flowers are exquisitely sculptured , with serrated, recurved petals of the most intense luminous red.

In Northern NZ it flowers all year long and is very vigorous, even tolerating pretty hard clay.

Clearly related to 'Psyche' is 'Swan Lake' which is tiny and dainty purest white, flowering in great profusion and growing very fast and tall. Amongst this dazzling virtuoso display, random branches appear that produce pink flowers which are identical in every other way. Cuttings grown from the pink branches (sold separately as 'Fantasia' ) eventually sport white flowers on some branches. Most odd, but rather lovely.

In Bali I have seen these growing two storeys high, and they also are very successful as tall standards. The strongly vertical growth needs hard pruning to maintain the floriferous youthful look.

A gaudy dazzler thats almost too much even for me is the Australian hybrid 'Lady Cilento'. Vigorous and hardy, she has waxy ruffled orange petals splashed with white and gold and a cerise eye. A startling sight among the more refined and elegant folk I've mentioned here, but the louder classes do add a touch of liveliness to any neighbourhood.

Finally, the aptly-named 'Tango' is a classy late-bloomer with a tendency to legginess without stern pruning. The huge flat flowers are a dark rust-orange in Summer with a crimson eye, but as the nights get cooler in Autumn, they become an extraordinary metallic bronze and will last for up to three days.

Keeping Hibiscus happy in our heavier soils can be difficult. A useful strategy is to build loose sandy soil up on top of the clay as a raised bed.

Large boulders and concrete or rock paving close against Hibiscus store a lot of heat and keep the roots warmer. This has allowed me to grow Frangipani outside in clay so should work well with Hibiscus.

(Copyright Russell Fransham 2004)