SHARING SECRETS: Australian Plants


Edited by Dayle Cheever.

Our January speaker raved about Australian plants, but sometimes they don’t do so well in San Diego. What success or failure have you had with Australian plants in your garden?


Lisa Bellora: I’ve had success with most Grevilleas (but not transplanting them), and difficulty with Chamelaucium. I’ve had success with Dianella, Lomandra, and Eucalyptus, of course.

Wanda Mallen: Aside from my cacti and succulents, I find Australian plants to be the most reliably easy to grow plants in my garden. Acacias, Melaleucas, and Grevilleas do very well in our Mediterranean climate. They need to be watered regularly for the first two years and after that, they’re very drought tolerant. They are also, for the most part, tolerant of poor soils, frost resistant, fast growing, and reliable bloomers. What more could you want?

Charlotte Getz: All of the Australian plants in my yard are thriving. I have a wide variety of Grevilleas. They have been planted from six months to four years. I live near the coast in Encinitas.

Carey Pratt: Success with Aussies in San Diego, for me, depends on the genus. I keep my drought tolerant garden very dry, so that may be a problem. Acacias are always successful, and easily grown from seed and easily available by mail from Australia. Acacia dealbata is fabulous if you have the space for a huge tree. A. covenyi, is a beautiful gray foliaged tree which hedges beautifully. Eucalyptus may be a good choice if you have the space and are careful about selection. Monrovia grows a smaller bush type, ‘Moon Lagoon’, with beautiful gray leaves. Callistemon are fairly easy, Grevilleas are terrific and easy, Melaleucas are reliable and tough, especially M. nesophila. Any Correa, especially ‘Ivory Bells’. Brachychiton is a favorite, especially B. rupestris. Boronias are generally delightful and easy small shrubs that are always in bloom. I have trouble with the Chamelaucium; I have killed many. Same with Leptospermum. Probably not enough water in my garden, as they’re both a little thirsty. I don’t fertilize any Aussies since they’re very sensitive to phosphorus. I just use my homemade mulch. (92106)

Rosemary Stark: I have only tried kangaroo paws. All six of my plants died.

Doreen Borseth: I recently had a backyard restoration that was completed in October of 2016. Susan Rojas was the designer and she primarily utilized succulents along with some beautiful Grevilleas. They have all done well with the exception of one that was water logged after repeated rainstorms. What I have learned is that they prefer well drained soil and they especially like the areas that have been built up (berms).

Linda Chisari: Billardiera heterophylla (formerly Sollya heterophylla) is very happy in my coastal garden. I love its clear blue flowers, which bloom over a long summer season. It has reseeded itself in several places, including my bed of natives, where it thrives with no summer water except the occasional rainfall. It has no pests of any kind that I am aware of.

Pat Welch: I am glad you asked this question! The main thing to remember when growing Australian native plants is never to give them phosphorus. Phosphorus is poison to plants from Australia. Australian soils are ancient and predate the creation of phosphorus on our planet. That is particularly true of soils in Western Australia. Southwestern Australia has the most ancient soils in Australia and a Mediterranean climate and native shrubbery, similar to our chaparral, and thus is a source of many of our garden plants. (Similar communities of plants are called “fynbos” in South Africa, “maquis” in the Mediterranean basin, “mattoral” in Chile, and “kwongan” in Australia.) Australian plants are used to growing in poor soil and it’s what they like best. Australian plants actually thrive here if we remember not to fertilize them at all or only feed them very lightly and never with phosphorus. Just look at Eucalyptus. No one would think of fertilizing a eucalyptus tree.

One of our loveliest climbing plants native to Australia is Hardenbergia violacea ‘Happy Wanderer’ (purple vine lilac), which blooms in winter with a final spurt of flowering in spring. Every late winter or early spring, Home Depot and Costco sell thousands of these climbers in full bloom. Almost every shopper emerges with one of these handsome plants in his or her shopping cart, yet never or almost never do these plants survive. The main reason for that is that folks tend to feed them with a balanced fertilizer containing ingredients for both growth and bloom. If you feed this to a Hardenbergia, it will promptly die. Yes, I mean it will begin to decline immediately and be dead as a doornail within a month or two. Nonetheless, I know a couple who have a lovely purple vine lilac in Del Mar that blooms massively every year on an arbor in their front yard. The secret to its survival is that these folks are not avid gardeners, but they are doing just the right thing for a Hardenbergia: They treat it with benign neglect and cut it back a bit after bloom just to take away the tangles. If you purchase one this spring, be sure to water it to get it established. After that, don’t over-water. Sunset Western Garden Book says ‘Happy Wanderer’ needs good drainable soil, but from what I’ve heard elsewhere, it will grow fine in clay soil. (If you have decomposed granite, it might croak.)

Tom Biggart: You must be careful when selecting Aussie plants for your garden as many of them are frost sensitive and others are quite picky about soils and drainage. When you find one that is happy, be prepared to stand back and be wowed for the rest of your life! Sorta like a good woman!!

Paula Suttle: Once in a while I lose an Australian plant, but normally I have wonderful success with them. I think it’s because my garden gently slopes down to a creek and they get good drainage. I only water them in the hot months and not very often. No fertilizer. I like varieties with soft foliage, as some are unpleasant to touch. I have a few nights of frost and they don’t suffer. I’m in Poway.

Jan Ryder: Well, I bought a Grevillea banksii that Mo Price raved about at one of our meetings last year. It is on a west slope with poor soil (mostly clay) and doing well despite my efforts.

Linda Morse: I purchased a Banksia and it lived for a few months and then died. I recall that when I purchased it, I was told to water it deeply once a month. Needless to say that it was on my drip system and that was not the watering schedule. I should have put the hose on it with a trickle once a month but I can barely remember to change the oil in my car, let alone baby a plant. Bye bye, Banksia!

Kate Engler: My wet clay soil doesn’t seem to support any of the varieties I’ve tried to date. I just bought another Grevillea and will try it in a pot with the planting mixture suggested by Obra Verde Growers.

Christy Powell: We propagated many Australian plants from seeds for the Australian Outback exhibit at the Zoo. We lost many seedlings early on, but once they got over a certain size, they seemed to do much better. Many plants took off once they got planted in the ground, too. Both in pots and in the ground, certain plants, such as Banksias, tend to get chlorotic, in our experience.

Candace Kohl: I grow a great number of Australian plants (and South African Proteacea) and was very sorry to be out of town for the last meeting. Many of mine are on a south facing and very sandy slope where they get drip water once a week. I have had many successes and a fair number of failures, some for unknown reasons. Some large bushes have looked just fine and in a week were completely dead, with no change in care. Grevilleas are the most reliable of the Proteacea for me and some of them are never out of bloom. They’re wonderful plants that provide excellent greens for arrangements. The Banksias are probably the trickiest, but very rewarding. I love the Melaleuca family and wish more of the interesting ones were available. They can be shaped, look spectacular, and are very hardy for me. I have M. incana, prostrate and draping over a block wall. M. diosmifolia and M. densa, are nicely shaped. I also have good results with some of the Australian cycads, and am especially fond of the smaller Macrozamia. I have quite a number of them that are doing very well. Those are the pots in semi-shade. I tried to grow the desert M. macdonnellii and was rewarded with the plant’s rapid death.

Joe Walker: When choosing which Australian natives you are going to plant, I think you need to consider plant varieties that can be grown in a Mediterranean climate similar to San Diego County. In San Diego County, we specialize in growing plants that thrive in our climate, which is similar to certain areas in Australia. We are able to grow a large and very diverse mixture with good results and have done so for decades. One of the problems we see in growing Australian natives in Southern California is water control. Gardeners tend to overwater these drought-tolerant plants, which brings on soil borne diseases that can kill these plants. We use a moisture meter, which takes the guessing out of when the plants need water. Soil types are also very important. Most Australian natives like a sandy, well-drained soil. They do not do well in heavy soil. We always recommend growers amend their soil when plants in heavier soil. Proof of how well some Australian natives do here can be seen everywhere by simply driving around our roads. Many varieties sustain themselves with no water or care and thrive by both growing and reseeding themselves.

Susi Torre-Bueno: The Australian plant I’ve had great success with is a Brachychiton acerifolius, or Illawarra Flame Tree (you can read all about it in the SDHS tree book). I purchased it at the U C Riverside plant sale in 2011, paying $10 for a one-gallon plant. Because I wasn’t ready to plant it in the garden right away, I put the pot on top of one of my vegetable garden raised beds. And there it sat, getting bigger every year, until 2016. By that time it was about twelve feet tall and very well rooted, through the holes in the pot, into the raised bed. One night we had a windstorm and the tree blew over, breaking off most of the roots. We took a chance and finally planted it in the garden in February 2016. It has grown several feet since then, and it bloomed last year for the first time. Such a resilient plant!


  

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