Ok, I have to own up to being something of a horticultural anorak: I like odd, primitive and deeply unfashionable plants.

Take horsetails (Equisetum), for example: I like the bolt-upright stripiness of some and the featheriness of others, but there's more to it. In terms of plant evolution they come somewhere above mosses (I also like some of these) and ferns (erm, yes), but the point is they have survived tens of millions of years on earth. And they're still here.

I still get the odd letter about why I should despise all horsetails, from gardeners and allotment holders who only see them as pernicious weeds to be despised and eradicated, my only crime being to write a short feature, several years ago, pointing out some can make attractive, ornamental plants. I even said in the piece some were invasive so were best grown in pots.

It's for a similar reason I love Wollemi pine (Wollemia nobilis): a coelacanth of the plant world, thought extinct for 20 million years then rediscovered less than 150 miles from Sydney, begging the thought what other floral living fossils are still out there waiting to be (re)discovered? How many more dawn redwoods, another example, which popped up in the 1940s?

I can blame my background in biology (although back then it was more animals than plants) for my abiding interest in evolution and the so-called ‘tree of life', but I don't know why most flowering plants rather leave me cold compared to conifers, cycads and ferns (although orchids are a notable exception that proves the rule). But I fear my main horticultural passion is thought weird, dare I say anally retentive, even in ‘planty' circles: bonsai.

The fact I can happily spend an entire day wiring every branch and twig of an unsuspecting bush in the knowledge that in four or five years time it may, if I'm lucky, come to resemble a full-sized tree I even find strange myself. As is the fact that a display of bonsai at a flower show can, still, stop me dead in my tracks and almost move me to tears. Which I guess makes me an anorak with Japanese leanings. Because I love their gardens too.