I’m slightly obsessed with pasque flowers and have a little collection that is multiplying slowly in the front garden. Their nodding bell flowers are held above a mound of perfect green, ferny foliage. Each flower has a central disc of golden stamens and if you look closely you’ll see that these in turn surround a cluster of tiny thread-like filaments in contrasting mauve or purple - the stigma. The stems and outer petals are covered in downy, silvery hairs, making them as tactile as they are beguiling to look at. You want to crouch down and stroke them like pets.

When the flowers fade the interest continues with their fabulous seed heads, which complement so many late spring and early summer plants. Mine soften the fading tulips and later wrap themsevles around geums, white valerian, centaurea and Cenolophium denudatum, staying intact for at least a couple of months into summer.

The common Pulsatilla vulgaris is native to Britain, its deep purple blooms usually in flower over Easter. There is also a white form, and other forms of P. vulgaris with different flower colours. I have ‘Rose Bells’ with gorgeous deep pink flowers and you can also get a deep red one called ‘Rubra’, and a pale pink one, ‘Pearl Bells’, which is next on my list to buy from Alpine specialists D’arcy & Everest.

I have two more unusual pasque flowers that I’m nurturing - two years old, they only have one solitary flower each this year, but I have high hopes they will bulk up eventually. Pulsatilla pratensis subsp. nigricans has tiny, elegant bellflowers in deepest purple, while P. vulgaris ‘Prima Papagena’ has flowers in variable shades of deep pink or red that have longer, narrower petals. They are usually semi double - mine, however, seems to be single.

My white pasque flower is a beauty, spreading out to completely fill a corner of one of the sunnier brick-edged beds. It seems to have self seeded as there is a baby plant right in front of it in the gravel outside the bed - but it has purple flowers, so the progeny must have reverted to the purple colour. Perhaps it’s just luck whether you get a white or a purple from a white parent? And perhaps now that there are other colours, they might hybridise naturally and I might end up with my own pale pink form instead of having to buy ‘Pearl Bells’ (which seems to be out of stock everywhere). Here’s hoping.

I also want to try growing them from seed, although being Alpine plants, they are slow to germinate, needing a period of cold weather to get them going. The best way is to sow them in late winter, covering them with a layer of grit or sharp sand and then just leave them in a cold frame to see what happens. I want to try the pale yellow P. alpina subsp. apifolia and P. vernalis, with silvery white flowers with a hint of mauve on the backs of the petals, both available from Plant World Seeds.

How to grow pulsatilla

Pasque flowers are undemanding little creatures, drought-tolerant and easy going once they are established, needing almost no maintenance. They like a spot in full sun and need very well drained soil - a gravel substrate is ideal - and when they are in the right conditions they may self seed. They don’t like being moved around, and can be slow to get going which explains the single flowers on the plants I put in two years ago. You can grow them at the front of borders mixed with other herbaceous plants, or just as single specimens in gravel or a rock garden.

A regime for box that will eradicate box caterpillar

Yes I know, perhaps a far-fetched claim, but I was in Belgium earlier this week and visited the nursery of Karel Goossens who has been growing and selling box for 35 years. Out of necessity he has developed defences against blight and box caterpillar, and feels that if we all did the same, we would be able to stem the epidemic of box moth that has hit the UK and Europe - and recently the US too. For the box caterpillar, Karel recommends spraying with Xentari or DiPel containing the microorganism Bacillus thuringiensis which will kill box moth larvae. It is an organic method that will not be detrimental to blue tits and other small garden birds who will also pick off the caterpillars from your plants. According to Karel, the caterpillars come out of dormancy according to day length and not temperature, so you can time the treatment very accurately each year. They are active between the end of February and mid May and after that the moths hatch.

The best time to spray is when you actually see the caterpillars on your plants, so you have to keep checking every week or so from the end of February. However - if you spray the plants at the following times, Karel claims that you can prevent any outbreaks in spring: July 10-15, August 15-20, September 10-15 and crucially October 10-15. That last application is the most important, because if you destroy any emerging caterpillars at this point, you won’t have a problem in spring. Karel explains: ‘During the second half of October the small caterpillars are spinning themselves in between two or three leaves: from that moment on the caterpillars are fully protected and you can’t kill them until they emerge in spring. If we all sprayed between October 10-15, we would eradicate box moth.’

If you have spotted box caterpillar this spring (as I have), then spray every two weeks if the temperature is warmer than 15C (which is when they are actively munching). Then make sure you keep spraying monthly on the dates shown above. I have already put these dates in my diary with a reminder and will spray them with Xentari, which is the easiest form of the Bacillus thuringiensis bacteria to get hold of in the UK. It comes in a powder form, which you mix with water and spray on your plants and is really not too much of a chore. Karel Goossens’ tried and tested regime has been adopted by many gardeners including Louise Dowding, whose beautiful garden at Yew Farm in Somerset has masses of artistically clipped box topiary. (Open via the NGS on July 6 and September 7). She says:

The suggested spraying dates are inked in my diary and the diaries of many buxus owning friends and visitors. Last year I did as the nursery suggested, concluding with the October treatment and this spring there is no sign of either caterpillar or moth. I am immensely grateful to them and their timely reminders on Instagram. They will save the noble buxus.

To prevent blight at his commercial nursery Karel uses fungicides so I asked him what he would recommend for organic gardeners. He made the suggestion of using whey. I had never heard of this before, but having done a little research it seems that it is a more common practice in the US. The theory is that the lactobacillius bacteria will colonise the leaves, leaving no room for fungal spores - and it works for powdery mildew too. I loved this quick video on it with added eye candy in the form of a pair of perfectly sculpted arms.

So now my mission is to try and get hold of whey in the right form - can we get dried whey powder here in the UK? Or do we have to make our own cheese or yoghurt to produce it ourselves?! Or should I be approaching our local dairy to see if we can use any of their waste product whey? If any of you are using whey already, I would love to hear more.

The other basic preventative measure for blight is simply to keep your box plants as healthy as possible. Mulching them each spring with an organic mulch will help to improve the soil fertility and keep the plants strong, and feeding them with a specifically tailored box feed like TopBuxus Healthmix once or twice in a growing season is a good idea. But don’t feed them with a nitrogen-rich feed, as the growth then becomes sappy and weak and therefore more susceptible to pests. The final tip I gleaned from Karel was to delay clipping your box plants until winter, rather than in June, which is the traditional time to clip in the UK. Your plants might look a bit more shaggy, but any open cut or wound on the plant immediately opens it up to disease, which in June is going to be more prevalent than in the winter.

If you have box that is already looking battered and blight-ridden, don’t despair. Feed and nurture the plants using the above regime, watering regularly if the weather is dry, and most plants will recover easily. Box is such a historic plant in the UK (and nothing really clips as beautifully into the same tight shapes) so I think it’s really worth fighting to keep the tradition going and not to give up on it completely.

By the way, Karel’s nursery, Buxuskwekerij Goossens near Bruges, sells the most amazing huge box and yew specimens, and it only takes an hour and a half to drive there from Calais. Follow him on Instagram @kwekerijgoossens.

Have a very happy Easter weekend everyone.

Clare x