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Growing Eremophilas in the Dandenongs
Hans Griesser
In the course of several outback trips, eremophilas caught my eye with their often bright and profuse flowers.
....but growing them in the Dandenongs, east of Melbourne, an area with wet winters, English style gardens with ubiquitous rhododendrons, azaleas, camelias, and the like?
....less than 100 metres from the Sassafras Creek Reserve where Mountain Ash and tree ferns dominate?
Always keen to experiment. I decided to try how many Eremophila species might adapt to what would seem to be pretty adverse conditions. Perhaps my experiences might be of some use to others to estimate the adaptability or otherwise of these marvellous plants to such cool-wet conditions, and help select species that might be rewarding garden plants in similar climatic conditions.
Located in The Patch, just uphill from Monbulk, my garden has deep, chocolate coloured loam topsoil that is quite acidic and drains very well, on a north-facing slope. Frosts and winds are not severe, partly because of protection by trees and tall shrubs along the southern and western fencelines. Before I got the "Eremophila bug" about six years ago, I had successfully established over 40 Western Australian Banksia species and 20 Dryandra species, indicating that drainage was good enough for plants from areas with much lower rainfall. But how would eremophilas cope with the moist winter air?
Well, quite a few species have prospered and flowered well, but others have not, as listed below. All are on their own roots except for a grafted E.mirabilis. The cost and very limited availability of grafted plants, and the ease of striking most eremophilas from cuttings, make it much preferable to grow them on their own roots. With the much cooler climate than their natural environment, I expected that growth would be much slower and often limited to the warmer months, but some plants flower very well even during the colder months. None have ever needed any artificial watering during Melbourne's summers, not even in their first year in the ground when I kept an eye on them for signs of water stress.
But attention is needed during winters. The problem is dieback of young branchlets, and if these are not removed in time, grey mould sets in, quickly expanding into an ugly grey mass and killing neighbouring branchlets. The browning off often seems to start at the base of the current year's growth. Often only a few branchlets die back and the gap is quickly covered up when new growth sets in, but occasionally there is more extensive dieback and some deaths as a result. Not unexpectedly, the problem is more prevalent with hairy-foliaged species, though interestingly some hairy plants have been little affected. Some other species can also be affected ... for instance Eremophila christophori, with its green leaves, shows some dieback every winter, but recovers quickly in spring, being a relatively rapid grower. Attack often, but not always, starts on spent flowers, and their removal certainly helps. However, this can be time-consuming for those species that flower during winter.
For many species and forms, my experience relates to several plants, up to five in some instances, as I often propagated from the first plant as soon as some cutting material was available. So here's my assessment:
Reliable eremophilas
The following are reliable species here, with good growth and flowering. They are good looking plants with no or little browning of branchlets:
E.maculata (several forms), E.maculata x racemosa, E.glabra green leaved forms (but not the "Murchison River" form, see below), E.oppositifolia, E.scoparia, E.weldii, E.youngii, E.veneta, E.biserrata, E.subterlineata, E.decipiens, E.drummondii, E.microtheca, E.bignoniiflora, E.bignoniiflora x alternifolia, E.laanii (pink form). The last three grow fast and quickly become leggy unless pruned regularly. The others need little maintenance. All have proved quite adaptable to this rather "unnatural" cool, winter-wet location in a sunny position and good air circulation.
Other reliable species (more or less!)
Many other eremophilas have succeeded to a greater or lesser extent, for example:
E.splendens: This is my favourite with its orange-red flowers, round leaves and very rapid growth, though it can become leggy quickly and needs regular pruning. Despite its hairyness, only occasional browning of branchlets occurs in winter, but this is not a real problem as the plant quickly re-shoots from below the point of attack, essentially saving pruning. A most rewarding plant in full sun and an uncrowded position, and easy to propagate as well.
E.maculata x duttonii (2 plants) and E.platycalyx: These are slower growing with fewer flowers but they are attractive plants. E.oldfieldii var angustifolia and E.abietina are similar although it's early days for these two (both 1 plant only and still relatively young, but growing steadily and looking healthy). All of these are worth a place in the garden here.
E.neglecta and E.tetraptera: These have shown very slow growth indeed - only a few flowers so far, but look OK and there have been no problems of browning/dieback. Suitable if you're prepared to be very patient!.
E.racemosa (white/yellow form), E.macdonnellii (several forms, green, grey-green, and grey leaves, purple and pink flowers), E.ovata, E.christophori, E.nivea, E.purpurascens: These flower well and look quite presentable in general. E.christophori, E.racemosa and E.purpurascens show quite rapid growth, E.nivea is not too bad, while the others are relatively slow. However, invariably some browning and dieback of branchlets occurs during winter but usually the plants recover well, though a couple of plants of E.macdonnellii failed to recover from winter damage. This species can be grown here but it needs frequent inspection during winter to cut out dead material and thus limit any attacks. With its more open structure, E.purpurascens is least prone to damage to adjacent branchlets. For E.christophori I find it necessary to remove spent flowers quickly during the wetter months, as this definitely is where attack starts, the non-hairy leaves not being a problem. For E.macdonnellii I remove spent flowers and green fruit once the humidity arrives in autumn - however, the grey-leaved forms also get attacked on stems and leaves.
E.bowmanii var latifolia: Surprisingly, this very hairy species has presented few problems (a very open position probably helps) but it is a high maintenance plant in this locality. I inspect it very frequently and remove all flowers and calyces as soon as the flowers finish, as they get attacked very quickly in humid conditions. Their removal prevents spreading of fungal disease to the leaves and branchlets. This species has relatively slow growth.
E.racemosa (pink/red form), E.calorhabdos and E.denticulata: These have fast growth, good flowering and very little dieback of young branchlets but much of the lower leaves turn brown and drop in winter, thus giving the plants a very leggy appearance that is hard to correct with pruning. They can be grown here but don't look their best - I have not managed to grow them to my satisfaction. However, one plant of E.racemosa (pink/red) in a large pot on the sunny balcony grew more slowly and kept many of the lower leaves; with regular tip pruning it has been maintained as an attractive, bushy plant that flowers well.
E.inflata: This species also loses a lot of lower leaves which makes it look a bit leggy, but as it is slower growing than the ones mentioned above, this is not a real problem. Its profuse flowering makes up for a somewhat sparse look.
E.densifolia and E.chamaephila: Both of these show slow growth with a leggy appearance due to dropping of older leaves and not responding well to pruning. They survive and flower but look sparse - not really satisfactory here.
E."enata": Only one plant of this species has been tried. It survived for three years and produced lots of flowers but made little vegetative growth. It died earlier this year from unknown causes but is worth trying again.
E.gilesii, E.spectabilis, E.latrobei and E.'Yanna Road': Only one plant of each of these has been tried. All struggled, producing some growth and flowers, and survived for about two-three years but produced considerable dieback and eventually died. I don't think these will adapt to this climate even in the sunniest spot in the garden. E.glabra 'Murchison River' is almost as sensitive - while growing well during summer, it is prone to extensive dieback or death in winter.
The only grafted plant in my collection, E.mirabilis, shows no problems but is not a rapid grower here.
In conclusion, more species than I might have expected have proved adaptable enough on their own roots to merit a place in the garden. However, in contrast with Western Australian banksias and dryandras, which require very little attention, many of the eremophilas I have tried need a fair bit of time and maintenance. This is partly because the much faster growth of many species calls for regular pruning and partly because of the need to remove dead material during the humid and cool months of the year to avoid fungal infestations that can quickly do considerable damage.
Some might say you need to be slightly mad to cultivate eremophilas in this adverse climate - but look at them when they flower in profusion!
Photographs by Hans Griesser except:
E.biserrata, E.denticulata, E.spectabilis - Colin Jennings
E.bowmanii, E.macdonnellii, E.racemosa, E.youngii - Brian Walters
Click on the thumbnail photographs (or the associated plant name) to view higher resolution images.
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Australian Plants online - September 2002
Association of Societies for Growing Australian Plants
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