This sounds like a daft question but, among the many mysteries that present themselves when you garden, this one often gets me scratching my head. How do those pests find plants to infest?

My garden was a field till I started changing it. It was just grass. I can’t even say that it was full of wildlife since it was, like the surrounding field, just cut twice a year to harvest the grass. There are few species present except some mouse ear, and a lot of docks. The nearest neighbours are a field away. So how did I get lily beetle on my lilies the first year? The first crop of carrots were attacked by carrot fly. That was slightly easier to work out because the hedges are full of cow parsley and that is host to this pest too.

Of course you can buy pests if you are unlucky. All the vine weevil in the garden must have come in with plants I bought. I recently bought a batch of perennials in pots and as I was planting them, found that the lower half of the pot was compost with no roots. A quick investigation revealed a massive swift moth grub and several vine weevil grubs. I have a never-ending battle with mealy bug on some houseplants and I know that that is because of a stag’s horn fern I bought and should have thrown out as soon as I spotted the problem.

But at other times it seems almost beyond belief that a pest appears. I was taking a break from some serious digging and replanting some beds the other day and checking for activity in the raised beds. These beds are proving a delightful respite from the other areas of the garden. Everything is on a small scale and it is nice to relax and weed little and often rather than hoe off swathes of weeds! Most of the plants, that I hoped would like the relatively well drained conditions, are doing well. I was happy to see that a patch of Tulipa clusiana was growing strongly in year two. I have previous experience of this in gardens and it tends to be pretty perennial. So here it was appearing again.

There are only leaves at present but it is a start. They looked like this last year.

But hang on – what are those green threads near the shoots

I didn’t deadhead the flowers and let the seed pods form and yes, there are loads of seedlings appearing. My joy was unbounded – well maybe not quite, but I was delighted to see them. So I leaned across the bed and took a closer look.

Incredibly, although the seedlings have only been above ground for a matter of days, there was an aphid, bold as brass! I apologise for the poor photo. Where did this aphid come from. I know that some aphids congregate on the bulbs over winter but there is no bulb here. Aphids can overwinter as eggs, which hatch in spring, after mating in autumn, but reproduction is usually by live birth and these surely can’t survive freezing temperatures in gravel? It is only one aphid, but I bet there are two today! And aphids spread virus diseases so this seedling may already be affected.

But it is not all bad news in the beds. The crocus ‘Blue Marlin’ has increased too and the mild weather has allowed the flowers to open, releasing their honeyed fragrance. Like all ‘chrysanthus’ crocus it has those distinctive globular flowers on thin ‘stems’ and with attractive markings on the outside of the tepals with a rich, golden throat.

‘Yalta’ is probably a hybrid of the prolific C. tommasinianus and (‘regular’) Crocus vernus selected by Latvian crocus expert Janus Ruksan. The contrast of the paler outer tepals and darker inner ones makes it distinctive – well on a warmer day than this!

crocus blue marlin, crocus yalta, tulipa clusiana