Last weekend I went down to the local Botanical Gardens and took the opportunity to check the progress of a few species that I’ve been wondering about for the forest garden.

The first was Decaisnea fargesii, also known as blue bean or, a bit more creatively, as blue sausage fruit. It’s a large shrub, maybe 4m or so, so just the right size for an allotment-scale forest garden, and better still it likes light shade. The eponymous sausage fruits are a stunning, almost metallic blue and are filled with a sweet, delicately-flavoured pulp, surrounding an inconvenient number of seeds. The ones in the Botanics looked and felt soft and ripe, so I’d say it’s a promising species for growing up here.

Next up was Sorbus torminalis, the wild service tree. There was a good crop of fruit, but they were much smaller than they are meant to be and rock hard. This is a fruit that is meant to be ‘bletted’ (i.e. stored over winter until they are almost rotting) and to be better after a frost, but these were so unripe that I seriously doubt that they will ever be worth it.

Two other Sorbus species were a different matter. The Sorbus lanata was covered in soft, ripe fruit a centimetre or so in diameter. They were mild-flavoured, sweet and with the pleasant mealy texture that sorbuses have when they aren’t rock hard. Like S torminalis, they are meant to be better after a frost, which I will probably be able to check any day now.

The other was Sorbus wilmottiana or Wilmott’s whitebeam. Sorbus species have the unusual ability to produce seed that is a clone of its parent, which has led to a lot of unusual clonal species scattered around the British Isles. Where a microspecies like this arises it is usually reabsorbed back into the parent species in a generation by interbreeding, but with Sorbus‘ unusual reproductive skills it can hang on indefinitely.

S wilmottiana is one of these rare species, from the Avon Gorge near Bristol. It’s too rare to start feasting on, but its soft, well-sized fruits left me wondering about the possibility of grafting a twig onto a native rowan.

If you have a botanical garden near you, they are a great way to check out what grows well in your area. They may have a good number of the species that you are interested in, all carefully labelled. I’m not encouraging you to go and start eating all their fruit – remember that one of the ways they may raise funds to keep going is by selling seeds – but it might be worth asking them about it. The people who run botanical gardens are, by definition, planty people who might well be interested in what you are doing. Our local one, the Cruickshank Botanical Gardens, has a ‘Friends of” group which allows you to get seed from the gardens every year – I have a small crop of blue sausages coming up from seed I got last year. If nothing else, you can collect that most valuable resource, information. As well as this year’s researches, I know from the Cruickshank that Amelanchier species are delicious, that medlar isn’t worth bothering with, that Camassia leichtlinii thrives in Aberdeen and much more.