Growing Acacias from cuttings.

[PD.]

I have noticed the question of acacias by cuttings has come up a bit of late, here is a little bit of info.

Wattle It Be? By Seed or Cuttings? by Tracey Perrott, Cannons Creek, Victoria.

Propagation of Australian wattles is traditionally done from seed, which is perfect for growing a huge range of Acacia species. Unfortunately seed propagation is not effective for selected cultivar forms, as seed from these plants is not always produced, and will rarely grow true to the parent. The prostrate selection of Acacia baileyana is a great example of this, as some years it will set quite large amounts of seed, yet the resultant seedlings are usually upright and quite variable. This is where propagation needs to be by asexual means, such as cuttings, to maintain good selections with desirable flower and foliage colour, or growth habit.

Growing Acacias by cuttings is not hugely difficult if you have good material, and there are many species and forms that can be grown fairly easily in this way. There are basic growing conditions that will make the job easier, although some experimentation will be needed to find the best method that works for you. Selection of cutting type, rooting hormone, hygiene, and date of taking cuttings, are other factors that may influence success or failure.

The main limiting factor is provision of ideal cutting material. By far the most consistent results are achieved from using container grown stock. This material tends to be less stressed, contains higher levels of plant nutrients and sugars; and is therefore able to sustain itself as a cutting much longer. By using healthy vigorous material, the cutting will have an extended life-span to survive until it is able to root and sustain itself. Acacia ‘Austraflora Cascade’ will strike reasonably well from cuttings off fresh young pots, yet cuttings from garden grown plants may have a very high failure rate, and tend to drop all or most of its foliage. The best material to use is fresh new growth that has just hardened off, with the stem still quite green and flexible. You can of course use garden grown material, but to maximise results you need to provide additional fertiliser and water so that it is growing very strongly. Keep in mind that new growth on larger plants that have not been recentlypruned, (whether in ground or in pots), will be less successful than the fresh growth following a hard prune. Use of more juvenile material will always produce better results, and good success can be obtained with shoots cut off fresh tubes.

The cutting environment can vary depending on your region and the location of your propagation area. The ideal growing conditions include provision of misting, which is critical in the warmer weather, particularly with Acacia cognata varieties. However in cooler periods, it is helpful tobe able to switch off the misting system. Rooting is enhanced with use of bottom heat, although this should not be above 20 degrees Celsius. Your propagation area should have medium light intensity, not located in full sun, norcompletely heavy shade. Success is possible without the use of bottom heat and misting, but rooting will take longer, and cutting stress is more likely. The propagation mix used with good success with most Acacia varieties consists of 10 parts propagating sand, 6 parts perlite, and 1 part peat.

Overall, good results are obtained using tip, stem, and heelcuttings of young material. Wounding can be beneficial, andsome species respond well to foliage cutting to reduce evaporation, although others may react by dropping their leaves. If the tips are very soft, they are better removed to prevent leaf scorching. A well known wattle is Acacia‘Scarlet Blaze’, which must be grown by cuttings to maintain the stunning red wattle flowers. During propagation trials, this plant was found to strike well from very young soft material taken from igloo grown stock. The shoots have barely hardened off, and the long leaves are not cut back. Use of garden material can have a very high percentage of losses.

Most Acacias will strike well with the use of IBA hormone rooting powder, at the strength of 1000 ppm, or 3000 ppm, for more mature new growth. Preliminary trials show some success with the use of IBA and NAA (1000/500 ppm) hormone combination rooting powder, and also with dipping in liquid hormones, at the medium softwood rate of 15mls/litre. There is some indication that rooting would occur without the use of hormones, although the percentage struck is usually much lower. Acacias with grey or hairy foliage are better treated with 1000 ppm IBA powder, and not kept for long periods under mist.

The best time to take Acacia cuttings is when the material is really good, usually in late summer and early autumn. Most species can be propagated in January, February and March (under mist) with good results. Basic hygiene of using clean material and equipment, adequate cutting spacing in propagating pots/trays to maximise ventilation, and use of a fungicide post propagation time is beneficial.

Propagation of Acacias is not highly technical. With the right material you can achieve good results with a wide range of garden cultivars. The following table lists some of the plants I have had most experience with. I hope this information encourages people to have a go at this wonderfully diverse group of plants.

there is a lil bit more information HERE including types of acacia, what cuttings to use, hormones etc.

Talking to someone that has experience in this field they mentioned while most acacias should be able to be grown via cuttings easily, the problem lies in finding the right material, time or year, hormones and conditions in which to keep the cutting till it strikes and of course some acacias are much much easier to clone than others. The trial and error involved is what often makes things very difficult. One thing they did mention that seemed to work well with all sort of cuttings was applying the hormone as a dilute foliar spray rather than the usual method of applying it to the base of the cutting. Id say a combination of both methods would have to work well, cant say for sure as i have never tried.

[Chiral]

Mmmmm nice one, practicing with feral trees could give you some more insight, developing your own little way to up the percentage that strike...particularly good news if we get this form of propagation down pat and can then look at cloning things like Phleb. I have tried striking cuttings in the past with no success...didn't really try hard though and no hormone used...the interesting part will be to find the best medium to strike them in...I'm thinking coarse sharp sand and a touch of loam from the garden...dunno, but I think that will the area that needs to be looked at, who knows rock wool may even work...how the cuts on tips/new growth are taken, sterile, side cuts, straight cuts, defoliation, some may need it some might not...need lots of people practicing and coming up with solid data on whats the best way.

H.

[G*P]

Thanks PD this is very helpful stuff

[Mr Stay Puft]

When i used to work at the Botanic Gardens they would do cuttings of most natives including Acacias... success rate was 50%, probably even higher, so they used to stick like 10-20 cuttings in a pot...

Seems the thing that led to better success was they way the stem was cut... leaving a 'tail' exposing as much of the vascular tissue as possible...

Other than that the next best method is aerial layering... this method can give even greater success and if done correctly the cuts should not die if they don't take!

[Mr Stay Puft]

Oh and failing both of those methods Acacias can also be grafted, so one may purchase a closely related common species, then graft cuts of rare species on to this rootstock...

This may also increase vigour, and reduce fatalities of those 'harder to cultivate' species

[G*P]

^im noticing that where the stem is cut, also makes a huge difference. Correct choice of stem, can dramatically increase success.

Some shoots appear very green even amidst the brown twig. Where the 'twig' is still green, seems to root far easier. This can be cut just below the little notches, yes?

[Chiral]

If someone could upload some pictures of exactly the right part of the wood to cut and at what angle that would help a lot.

H.

[Monk]

Great info, thanks!

Oh, and I too would appreciate more specifics about best parts of stems to use for rooting material...

Also, anyone rooting A. acuminata seedlings have any info particular to them?

[ferret]

I've been thinking of trying a few other methods in trying take cuttings from some Acacia's. Haven't head of this solvent dissolved hormone method before. Also might try my hand at some grafting also since I have a few seedlings on hand to try my hand at. Keen to hear of any methods people have tried in the past.

IA Dawson and RW King. Propagation of some woody Australian plants from cuttings

Australian Journal of Experimental Agriculture 34(8) 1225 - 1231

Abstract

For successful propagation of some woody Australian plants by cuttings it was beneficial to dip the lower 2 cm of the stem in an ethanolic solution of indole-3-butyric acid (IBA). For Chamelaucium uncinatum (Geraldton wax), 90% of cuttings rooted following treatment with the optimal IBA dose of 4000 mg/L for 40 s, while non-treated cuttings rooted poorly or not at all. After 21 days each rooted cutting had formed 4.2 ¦ 0.4 roots, with each root having an average length 42.5 ¦ 3.2 mm. Powder formulations of 3 g IBA/kg talc (0% rooting after 21 days) or a commercial preparation containing 0.05 g ß-naphthaleneacetic acid (NAA) and 0.02 g indole-3- acetic acid (IAA)/kg (30% rooting after 60 days) were less effective. When rooting was rapid, with extensive root formation within 3 weeks, >90% of cuttings survived transplanting. Rapid rooting required the bottom heat of the propagator to be run at 25-30¦C when air temperature was maintained at 20¦C. Rooting was good (85%) for cuttings taken from parent plants grown at 24/19¦C (day/night) and 18/13¦C but was less (43%) for cuttings taken from plants grown at 30/25¦C. Propagation is usually less successful where the stem is woody rather than young and fleshy; parent plant condition, therefore, will have some effect on propagation success. Sixteen other woody Australian species examined also rooted well when propagated with a quick dip in a solvent-IBA mix and had a similar positive response to root-zone warming.

Nelson, SC. Grafting of Acacia koa Gray Onto Young Acacia Seedlings

Native Plants Journal - Volume 7, Number 2, Summer 2006, pp. 137-140

Indiana University Press

Scions of Acacia koa Gray (Fabaceae) were grafted onto rootstocks of A. koa, A. mangium Willd., and A. confusa Merr. using cleft or splice grafts applied to very young seedlings. This is the first report of grafting success between A. koa and any Acacia species. Acacia koa scion plants at the second true leaf stage of development were joined with the Acacia rootstocks of similar phenology just below the cotyledons. The initial grafting trials resulted in success rates from 20% to 70%. Graft unions were completely healed within 8 wk, and plants were ready for transplanting at about 3 mo. These methods allow for the production of grafted A. koa seedlings with potentially increased disease resistance, improved horticultural performance, and potentially wider adaptation to Hawaiian ecosystems and landscapes.

[ENtiTY]

I don't think that the whole of the acacia genus will prefer the same material for striking...

Semi hard is where I'd start though, not soft new growth and not old growth, the bit between the 2. Collect your material and place in a CLEAN bucket of water. Hygene is extremely important and you don't want the cuttings to dry out. When ready to stick the cuttings, remove all the leaves accept for the top 2 and cut them in half. Now cut just below an internode at an angle, dip in a semi hard hormone and gently place in mix. You want sharp clean cuts with minimal bruising so use sharp CLEAN secky's. A special pair of secky's just for cuttings is best.

Disease management is half the battle with propagation via cuttings so make sure everything is CLEAN!

[DarkSpark]

There is an area of land near my house which has been cleared for development around 2 years ago but held up in red tape... the knocked a lot of acacias down and it would appear quite a few branches and so on have been half buried. they churned the soil around a year ago and leveled it and since i have noticed an abundance of acacia "seedlings" growing. however i dug one out to try and get it home to find it was attached to a small twig around 10cm long and 1.5cm thick with roots shooting off the stick. There are shitloads of them growing and i am not 100% sure if they have all grown in the same fashion but this would surely indicate that cloning cannot be THAT difficult... I will go dig a few more out over the next few days to check (they are starting to move machinery back in and from what the council told me starting to build and every tree on the block will be leveled to build a housing estate so yeah. its either me or the machines ;) will get back to you all on what i find...

As for actual cloning techniques, Harry has stated pretty much exactly how i have recently tried to take some and will be seeing if they take *fingers crossed* i have seeds from a few of them anyway though so its not much of an issue if the clones don''t take as i will have a fair few seedlings shortly also with some of the species, i.e. Acacia Podalriifolia(spelling?) you would want to take the older branches which have lost the furriness, this isn't from practice more of an educated guess, but the older more "proper" branches would be a much more suitable candidate for cloning (in my opinion)... the silvery ones seem way to soft etc...

cloning is much the same in principle for all plants... sterile tools, angled cut under the internode, remove the majority of foliage, cloning powder/gel/whatever, into the clone box... I just used my clonex purple as it is what i have may not be optimal but shuold do fine.

and chiral, i like to take clones an inch or two under the nodes and put upto just below the node in the ground ( have found having nodes under the ground seems to increase the chance of rot forming, other say the opposite but i stand by my ways ;)

Edited November 26, 2009 by DarkSpark

[t st tantra]

usually its suckers from the old root system....

t s t .

[Mycot]

When i used to work at the Botanic Gardens they would do cuttings of most natives including Acacias... success rate was 50%, probably even higher, so they used to stick like 10-20 cuttings in a pot...

Read an article on acacia cutting propagation several years ago where it was mentioned that when there were several cuttings per pot much higher strike rates were achieved than when there were single cuttings per pot.

The same article also mentioned that species with thicker cortex's had lower strike rates. Wounding or thinning the cortex with sandpaper may improve outcomes in these cases.

High rates of rooting compounds are generally used for this difficult to root genus.