Tuesday, September 15, 2009

Saving The Avocado Tree

I'm in a frenzy of clearing, planting and mulching. This week I got someone in to mulch the huge pile of tree branches that I'd cut down over winter. This made about 2 cubic metres of great mulch, which has gone on the new Bromeliad garden, the Avocado tree and the strawberry patch. I'm hoping that this will cut down my weeding this summer, which will pay off with more days floating in the harbour on my back, or fishing off the rocks at the beach. That's the theory anyway.

It's amazing how much vegetation can be chopped out in only a half acre section. Aside from the mulch, I've also cut nearly 3 cubic metres of wood for the fire next winter and filled all 4 compost bins, each another cubic metre. Mostly this is scrubby self sown natives, but also many noxious weeds and some prunings from overgrown fruit trees. I think this property had every noxious weed listed for the Auckland region.

The Avocado is a bit of a project. The tree was nearly dead when we arrived two years ago, with almost no crop and hardly any leaves. Everyone has been telling me that Avos don't survive at the Point, on account of the peat soil being loaded with the dreaded phytophthora root disease and the sandstone layer only about half a metre below the surface. Strictly speaking they are correct, as Avocado trees prefer a deep free draining soil with at least 1m of soil before you reach any hard pan or poor drainage.

Of course that is like a red rag to a bull, as nothing is impossible for a fanatic. Anyway, after two years of mulching, applying gypsum, clearing away the arum lilies and fertilising, I have a tree that still doesn't look great, but at least it has a crop of about 150 fruit and many more leaves than before.

Mulching is the absolute key to success with Avos. A good layer of woody mulch helps keep the weeds down, feeds the microorganisms that fight Phytophthora, evens out soil moisture and provides a nice slow release form of fertiliser. Most importantly though, the feeder roots of Avo trees are designed to creep about just below the leaf litter layer and a layer of mulch is the best way of ensuring these roots stay healthy and white, maximising their ability to take up nutrients and water.

No comments:

Post a Comment