Sunday, July 22, 2007

Esperance Hakeas

Very hardy with attractive flowers, interesting foliage and sculptured growth habits.

Hakeas are often the neglected genus from the Proteaceae family, yet there are over 150 species and between them, they do everything their closest relative Grevillea does and often more. For a start hakeas are endemic to Australia occurring nowhere else, grevilleas on the other hand are also found in Sulawesi, New Guinea and New Caledonia, although Australia has many more species.

Physically there are a couple of distinct differences between Hakea and Grevillea, most noticeably are the seed capsules, which with Hakea are thick and woody, plus (with most species) do not open to shed their seed until the plant dies or is burnt in a bushfire. Grevilleas on the other hand have much thinner seed capsules, which release their seed annually.

A common misconception is that all hakeas have sharp prickly foliage. This is certainly true with a number of species, but many have flat blunt leaves and even some with needle-like foliage, are quite soft to touch. So there is considerable variation.

Below is probably the best known and widely grown Hakea, ie Hakea laurina or the Pincushion Hakea. This species not only has beautiful and unusual flowers, but flat unarmed foliage that with some forms weeps to the ground. It is quite common around Esperance, from coastal areas to around 100 km inland.

Pincushion Hakea, Hakea laurina

Another difference between hakeas and grevilleas is the foliage. With flat foliage (like a conventional leaf) each side of the Hakea leaf blade looks the same; in other words there is no top or bottom to the leaf. Whereas with grevilleas, the top side is markedly different in appearance to the underneath (bottom) side.

The strongly honey scented Hakea corymbosa or Cauliflower Hakea, so called as the flowers form in tight cream/greenish clusters and it really does look like a cauliflower. It occupies a similar range to the Pincushion Hakea above, but is more common in low lying areas around swamps. It grows as a very compact bush to one and a half metres.

Cauliflower Hakea, Hakea corymbosa

Although not always the case, hakeas tend to grow in areas of periodic flooding or in seepage zones, whereas most grevilleas prefer better drainage. This adaptation to low lying areas does not necessarily mean they are more difficult to grow, as typically these habitats are ephemeral regarding the presence of moisture and often dry out completely during summer, meaning most hakeas are really tough, being able to withstand wet and dry conditions.

Around Esperance the Hakea varia or the Variable-leaved Hakea, is often found growing around freshwater swamps alongside the Cauliflower Hakea above. It too is strongly honey scented and structurally interesting, often growing into unusual sculptured shapes. It is called the Variable-leaved Hakea because the leaves can be smooth edged or highly toothed, with many variations between. The form near me tends to be very spreading and rarely exceeding a metre in height.
A naturally sculptured Hakea varia, around a metre in height x 2 metres diameter.

The same Hakea varia photographed at night.

Variable-leaved Hakea, Hakea varia

I regard myself as being very lucky to have a third Hakea growing with the above Cauliflower and Variable-leaved Hakeas. It too has honey scented flowers and highly variable foliage, however growth wise it is a more normal spreading shrub to around 2 metres in height. Its name is Hakea trifurcate or the Two-leaf Hakea. Note the broad leaves alongside the finely divided ones. These can vary tremendously, with some plants being mainly broad leaved, whilst others all finely divided. There seems to be little reason why this should be so, other than those plants with broad foliage tend to occupy the better watered areas. These hakeas are widespread in the WA Wheatbelt and prefer seepage zones, often around swamps.

Two-leaf Hakea, Hakea trifurcate

As with grevilleas, Hakea flowers vary in composition, forming long or short brushes, plus large and small flower clusters. Hakea flowers also come in a variety of colors, plus some have highly colorful foliage.

Hakea victoria or the Royal Hakea is not an Esperance species, but grows down the road a little in the East & West Mt Barren area, ie on the coast from Ravensthorpe and would probably have the most colourful foliage of any Hakea. It is quite a tall shrub with some growing to over 3 metres. It prefers sandy soils over granite or heavier loams.

Royal Hakea, Hakea victoria

To further emphasise the variability of this genus, some hakeas grow into large dense shrubs or small trees; others are small and spindly, with everything between. Still others grow into living sculptures, providing interest even when not in flower. The foliage (as shown above) is ridiculously variable, but so too are the seed capsules. These can be smaller than your fingernail, or almost as big and round as a cricket ball. Others growing into amusing shapes, like the Frog Hakea.

There is even more to hakeas; birds feed from them, find protection from predators and larger birds, or build their nests within their foliage, particularly if prickly, so these plants occupy a strong ecological niche not only in the bush, but also in your garden.

To end with, I present Hakea clavata or the Coastal Hakea (Not a good common name), which only grows on granite outcrops ranging from the coast to inland mallee regions, where very common. It is a bushy shrub to 2 metres in height and grows in shallow soil over the granite, where its roots will penetrate into any fissure. Due to the hot drying summer conditions it is often the only sizable plant on an outcrop, and does this by producing thick fleshy leaves (almost succulent) to conserve moisture. It has developed another necessary survival mode different to most hakeas whereby it releases its seed annually without the need of bushfire. This is important as most fires cannot traverse the often large open areas of bare rock, making the usual method of seed release (after fire) largely redundant.
Coastal Hakea, Hakea clavata

There is a Hakea for almost every garden situation including the most difficult, so if you ask at your local Garden Centre, you will probably be surprised by the variety of tough and interesting plants available.


buffy said...

I recall another supposed "virtue" of H. salicifolia (Willow leaved hakea, Eastern states) being fire retardant qualities. I remember planting a "hedge" of them on the north and western sides of our property years ago. Whether they really were fire retardant was never tested....but the yellow tailed black cockies loved them and pruned them every year! Are any of the Westerners supposed to have this quality?

Esperance Blog said...

Hi buffy, an interesting question of which I am not sure I can answer.

Maybe the hakeas, or at least H. salicifolia have fewer oil glands to ignite, also moisture laden fleshy foliage, ie new growth, is also less likely to ignite. However in bushfires of today with all the accumulated fuel and resultant large fires, just about all vegetation will burn.

Interesting however, with aboriginal fire management and hakeas tending to grow in water collection sites, they and other vegetation can be difficult to ignite owing to their moisture uptake.

Do you know if the H. salicifolia seed capsules open without fire?


buffy said...

Yes Jack, the seeds used to open without fire. I remember picking out the papery seed surround with tweezers a couple of times in a vain attempt to propagate. I didn't know much then.

buffy said...

A quick Google suggests "damage or fire" release the seeds. So the plants could have been responding to the cockatoo pruning.

Esperance Blog said...

That's interesting about the seed capsules opening on their own. This suggests to me that they are as you say 'fire resistant' and probably grow in an environment that is seldom burnt. Just gos to show how well adapted these plants are to their natural environment.

From memory, Hakea salicifolia is another broad leaf, non prickly species, with attractive pink/red new growth.

Thanks for the information.


Esperance Blog said...

>>A quick Google suggests "damage or fire" release the seeds.<<

That's a bit of a general motherhood statement I think buffy, as most hakeas do this. Unless the species has actually been studied and specifically referred to as not shedding their seed unless damaged or burnt, I would regard it purely as genus generalisation.


Gaye from the Hunter said...

hi Jack, an extremely interesting post. Hakeas are such diverse plants and I am amazed at your last picture showing the succulent-like leaves.

I was also very interested to learn about Hakeas dependence upon fire.

I have not seen any "attractive" Hakeas in the Hunter Valley growing in their natural environment. I have seen some that appear to have a very short life span. I wasn't aware that some did not open their seed capsules until the plant died, so this is possibly what these plants are doing.

I have recently found a local area of accessible bushland that has hakeas that I haven't previously noticed locally. As the season progresses, I will take note of their habits.

Thank you for sharing your Hakea observations. It has encouraged me to take a closer look at my local Hakeas that I had previously overlooked in favour of seemingly more "interesting" plants.


Esperance Blog said...

Thanks for your comments Gaye. The thing about nature I find, is the more you look into things, the more interesting you find them. It rarely fails.

Good luck with your Hakea hunts.


Podzol said...

>>The thing about nature I find, is the more you look into things, the more interesting you find them. It rarely fails.

That is so true!

I loved your hakea blog. They are so stunning, the flowers just make me swoon. Great photos! Thanks!

Esperance Blog said...

Thanks Podzol


Anonymous said...

Mighty fine effort here Jack just like all your blogs. The hakeas are a magnificent plant and thanks for showing them.


Esperance Blog said...

Thanks Headsie, your comments are much appreciated.