Sometimes I talk about how filling your garden with plants is the best thing you can do to improve it for wildlife.

But if you can choose those plants with care, you really boost things to another level.

And one plant I wouldn't do without in my garden is this:

It is Garlic Mustard, a native member of the cabbage family, found across almost all of the UK on hedgebanks and in open woodland.

It is this habitat preference that gives it the ending of its country name - Jack-by-the-hedge. The 'Jack' part? The most likely explanation is that 'Jack' was one of the names given to the Devil in olden times, whose breath was said to smell of garlic. And fresh, young Garlic Mustard leaves indeed have a rather garlicky taste. In fact, many human foragers today continue to pick it, although its other name of Poor-man's Mustard gives you a sense of its palatability.

Putting aside itsslightly iffy value as spring greens, I think it has a lovely fresh look about it at this time of year, with the smart, jaggedy-edged leaves and the smattering of small white flowers on top. Here it is at the back of my gravel garden this week (behind the red poppies. The white in front of the poppies is Sea Kale; the white to the left of the poppies is Perennial Candytuft):

It is not a bad flower for attracting hoverflies, such as this drone-fly:

But here's why I really love it: it is one of only two main foodplants of the Orange-tip butterfly.

Ok, so the female Orange-tip doesn't quite live up to the name, but you can tell she is indeed an Orange-tip by the lichen-patterned undersides to her rear wings. Beautiful.

And here is her male (nectaring on Ground-ivy). The wings are stunning; the green speckled eyes are amazing!

The fun bit is then seeing if the females have done their duty and laid eggs. They are laid singly, on the underside of a flower stalk, and the eggs are bright orange. And I'm pleased to say my female Orange-tips have indeed been busy this week - spot the egg!

Oh, and two final things about Garlic Mustard. One - it is so easy to collect as seed and grow.

And, second, it is not only the Orange-tip that lays its eggs there. Green-veined White and Small White butterflies do, too. So if you enjoyed spotting the Orange-tip egg, try going back to the first photo in this blog and spot the Small White egg. Hint - it is pale, and laid on the underside of a leaf!

If you want to drop by my RSPB wildlife gardening blog, it is updated every Friday, and I'd love to see you there - www.rspb.org.uk/community/blogs/hfw