What to feed Australian native plants, and what to avoid

The reason natives get their own bag

Most people work out fairly quickly that natives are less trouble than an exotic garden, and then assume that means they can be fed the same way as everything else, which is where it goes wrong. Australian soils are old and heavily weathered and they are low in phosphorus compared with almost anywhere else, so a lot of our plants evolved to make do with very little of it and got very good at pulling it out of the ground.

Give one of those plants a rich general fertiliser and it does exactly what it has always done, which is take up phosphorus efficiently, and it takes up far more than it can use. The plant goes yellow between the veins and the leaf tips burn. In a bad case it dies without ever having looked obviously starved or obviously overfed.

Which natives actually care

Not all of them are equally fussy, and it is worth knowing which ones are, because the careful gardeners often end up underfeeding a plant that would have been perfectly happy.

The family to be careful with is the Proteaceae, which covers grevilleas, banksias, hakeas and waratahs. Those are the ones where a high phosphorus fertiliser does real damage. Things like eucalypts, melaleucas, callistemons, wattles, lilly pillies and kangaroo paws are much more forgiving, and a native specific fertiliser suits all of them anyway, so the simple rule is to use one bag across the native bed and not think about it again.

What a native fertiliser is doing differently

A native fertiliser is formulated low in phosphorus rather than being a weaker version of a general one. It still carries nitrogen for leaf growth and potassium for flowering, and the good ones are organic based so the nutrient comes out slowly as the soil breaks it down instead of arriving all at once.

That slow release matters more with natives than with anything else in the garden, because the whole problem you are avoiding is a sudden load of nutrient in the root zone. Read the rate on the bag rather than eyeballing it, because it is a different rate from the one you would use on a veggie patch.

When and how to put it out

The main feed goes on in early spring as the plant starts moving, and you can follow up in autumn if the plant is working hard or the soil is poor. Skip feeding in the middle of summer, because pushing new soft growth into heat and dry is asking a plant to do something it has no water for.

Scatter the granules out to the drip line rather than around the trunk, which is where the feeding roots actually are, and keep them off the stem. Pick a still day so the lot does not end up on the lawn. Water it in properly afterwards, and mulch over the top, because mulch is doing more for a native garden than the fertiliser is on most blocks anyway.

The bit that matters more than feeding

Honestly, if you only did one thing for a native bed it would be mulch and not fertiliser. A good layer of coarse mulch holds the soil temperature steady and stops the surface drying into a crust, and it slowly feeds the soil as it breaks down, which is much closer to how these plants live in the bush than a granule ever will be.

Keep the mulch back off the trunk by a hand span, because a collar of damp mulch against bark rots it. And go coarse rather than fine, because fine mulch mats down and sheds water instead of letting it through.

A note on potted natives

A native in a pot is a different situation, because there is no soil reserve to draw on and everything you put in washes out the bottom over time. Those ones do need feeding more regularly than a native in the ground, at a lighter rate, and a native specific product is even more worth using because there is nowhere for an excess to go.

Shop related products

• D.T. Brown Australian Native Flower Mix, 500 seed pack. A cheap way to fill gaps in a native bed.
• Neutrog Whoflungdung Mulch 20kg. Mulch that breaks down into the soil rather than just sitting on it.
• Easy Wetta Garden Mulch 50L. A coarser garden mulch for covering a bed properly.
• Manutec Soil pH Test Kit. Worth doing once if a native is sulking and you cannot work out why.

Did you know we stock Neutrog Bush Tucker in store, in the 4kg and the 20kg, and it is not on the website. That is the native specific fertiliser this post is about. Give us a ring on (08) 8536 4333 to check what is on the shelf.

The rest of the range is in garden products and the Neutrog lines we have listed online are in Neutrog garden products. A 20kg bag is awkward in a car, so our local delivery runs Tuesdays and Thursdays, $5 around Strathalbyn and $10 on the regional run.

Keep reading

• How do I plant a tree?
• How to build better soil in any garden
• How to get good bugs into the garden and keep pests down

I am firmly of the view that the natives are the only part of my garden doing well despite me rather than because of me.

Candeece