A guest post by Tiki Swain*
My dead tree bed is a tricky space, an ongoing garden experiment.
The dead tree was once a citrus, but it didn’t survive the droughts Perth endured in the last few years. The old Italian grape vine sprawling over it however managed fine.
My initial idea was to remove the dead structure and make a mini-citrus orchard. But as I studied the garden system as a whole, I realised that plan was doomed to failure. The droughts of the last few years will become the norm within a couple of decades, and as this garden is intended to last for 100 years I have to assume those conditions in all my choices.
The dead tree bed is the farthest corner on my property from water access. I can reach it with a super-long hose if I set the nozzle to “fly high” and point-and-shoot from about six metres away with perfect parabolic angle, but that’s about it.
The adjacent corrugated fence presents a few challenges too. It is a thermal sink – albeit not too large – but on any warm day it’s radiating heat all afternoon. It does give shade, but it’s hot shade when the sun strikes the other side of it. And it makes a huge rain shadow too, given that much of our better rain comes from that direction.
The soil back there is poor even compared to the rest of its surroundings, and – like all of the garden – it’s off-the-scale water resistant, or hydrophobic. (Literally off the scale – I did the test myself and I couldn’t get any concentration of reagent to penetrate).
Put all that together and it’s no surprise the soil, or rather sand, is dry. Bone dry.
The weeds grow thickly in spring, but their stems are so slender and tough compared to their species-mates just four metres away you can see that it’s only the most-dry-loving variants that are surviving, and they’ve got all their epigenetic switches for drought turned to ON. (An epigenetic switch is something that turns genes ON or OFF based on external conditions such as drought, famine, malnutrition, poverty. Which genes are activated or silenced is never the only factor in how something grows, but it has an influence).
The saving grace of this space is the grape vine. Without it, this sand would sunburn. With it, although the ground stays bare and weedless all through summer, it’s not ‘cooked’. The seedbank remains alive. So I can make this area a seasonal meadow. The trick is to use plants that don’t need to germinate in autumn. It takes ‘til midwinter for the soil profile to get enough rain through it for young plants to survive.
I tried autumn sprouters the first year: flax linseed and quinoa, but no success. This year I’ve gone for garlic. This plant sprouts at midwinter, harvested or dies back in late spring / early summer and is done by the summer solstice. So it’s thriving in the light while the grape vine has no leaves, and then sleeping underground through the hot season. The timing is much better.
Of course, the soil is still crap. I have much work to do to make it able to convince plants that they’re not about to die, and even more work to do to replace the weeds I don’t want. So it’s an ongoing project. But we’ll see how it goes this year, and reassess methods and plan next year.
*Tiki Swain is interested in everything and pays attention to as much as possible, especially if it’s food, plants or primitive skills. She is a former science communicator, now studying urban farming and writing about the interplay within agricultural systems at AgriTapestry. You can find her on twitter as @tikiwanderer