A ripe sour plum on a street tree

Sour plums are ripening on trees across Adelaide right now — trees I’d never before noticed bear fruit.

They’re supposedly ornamental, you see. No one pays them much attention, not even the birds.

It was the splattered pips of dropped plums on footpaths that finally clued me in to the awaiting bounty.

A sour plum tree in an Adelaide street.

So off we wandered with a bucket and a beer, and foraged some from a suburban street near our place.

By the way, foraging is rather a nice demonstration of permaculture principle 11 – ‘use edges and value the marginal’. It underscores the idea that the margins or fringes are often a powerhouse melting pot of action, friction, biodiversity and ideas.

As permaculture co-originator David Holmgren says (in this video by the Milkwood crew): “That word ‘marginal’ has come to mean ‘of no value’. But that’s in fact wrong. It’s those things which are valuable in providing back-up.”

Foraged sour plums in a bucket.

So, the plums were foraged from the edge of the street. Now, what to do with them?

They certainly live up to their sour name … cooked into a jam or a pie, perhaps? Could chutney work? I found a recipe for a Chinese sour plum tea (suan mei tang), which required hawthorn berries too — we still had some leftover from our autumn foraging adventures.

I couldn’t decide. So I put the call out on Instagram, and was promptly given the perfect solution by Georgia: a shrub syrup first, which would leave loads of yummy, mushy, sweet fruit leftover for a second recipe.

Two things from one lot of fruit. Win.

Plum shrub and plum upside-down cake

Foraged sour plum shrub syrup

First up, what the heck is a shrub? (Aside from a small bush, which I was quite sure we weren’t making here…)

A shrub is a concentrated syrup that combines fruit, sugar, and vinegar. The result is a sweet, acidic mixer that can be enjoyed on its own or used in a variety of mixed drinks.

So say these folk.

The term “shrub” is apparently borrowed from the Arabic word sharāb meaning “to drink”. And it’s good for you! Apple cider vinegar can help with a bunch of inflammation-related and skin conditions.

OK, now to the recipe…

The finished plum shrub
When taking pictures of the finished product, it’s helpful to spell ‘shrub’ correctly…


1kg of foraged sour plums, seeds removed (or normal plums, or any fruit, really)
300g sugar (or 200g if using normal fruit, rather than sour plums)
About 200g apple cider vinegar

You can also add your own flavours. I added a teaspoon of vanilla bean paste. Additions Georgia recommended included bay leaf, black pepper, thyme or orange rind.


Place the plums and sugar in a large jar or bowl and give it a mix. Pop the lid on and chuck it in the fridge, which will prevent the lot from fermenting.

Allow the fruit to macerate (slowly grow softer and release more liquid) over about four to five days, giving it the odd stir every now and then.

When you’re happy with how it’s looking, drain the syrup off — keep the fruit, as this will become the yummiest addition to the upside-down cake, or any other treat you might like to whip up.

What the plums look like when fully macerated
The result at the end of a few days’ macerating — yum fruit ready for a second purpose + a delicious syrup for making shrub.

Measure the syrup and add add half as much apple cider vinegar — a 2:1 ratio of syrup to ACV. Taste a little along the way to ensure you’re not going too OTT on the vinegar.

Pop into a bottle and keep in the fridge. Use as a cordial, added to rainwater or soda water. Yum!

Plum shrub - ready to drink

Foraged sour plum upside-down cake

So, if you’ve made the plum shrub, you now have a heap of delicious and perfectly useable macerated plums leftover. Enter: the cake.

(Or just use whatever fruit you have. That’s fine too.)

Upside-down plum cake
Yes, I forgot to take a proper photo of the cake, as I was too intent on eating it…


175g butter, at room temperature
2/3 cup brown sugar, or a little less if using normal plums
The leftover fruit from your plum shrub, probably about 700g
1 cup caster sugar
1 teaspoon vanilla paste
2 eggs
2-3 tbsp white chia seeds (or add an extra egg, if you don’t have these)
1 3/4 cups plain flour
1 teaspoon baking powder


Preheat the oven to 180C. Line a round cake pan with baking paper — buy an eco/paper-only version if you can, as regular baking paper has a thin lining of silicone, which means it can’t be recycled or composted and has to be thrown into landfill.

Drop 50g butter into the pan and pop in the oven until the butter melts. Remove from oven and sprinkle with brown sugar. Place the plums over the top, spreading them evenly across the base.

Using an electric beater, beat the remaining 125g butter, caster sugar and vanilla on high speed for 4 to 5 minutes or until pale and creamy. Add the eggs, one at a time, beating well after each addition.

Add the flour and chia seeds and gently fold in until mixed through, without overmixing. Spoon the mixture over the plums and smooth out the surface.

Bake your cake for 50 minutes or until a skewer inserted into the centre comes out clean. Stand the cake in the pan for at least 10 minutes — I left mine to cool completely, as it was rather juicy.

Turn out onto a serving plate and marvel at its beauty before devouring.

The plum shrub and upside-down plum cake go quite well together.