The walnut trees are flowering now. You might blink and miss the event though. The dangling male catkins don’t last all that long, especially if the wind gets up at all. The female flowers are tiny, opening at the ends of the spurs or tips.
Walnut flowers, female flowers on Juglans regia, the English walnut
They are tiny, but cute, with sticky, bunny-ear-like stigma. They typically appear in small clusters (2-5 nuts) on the English walnut, Juglans regia.
The sticky stigma are reminiscient of rabbit ears
I have one (an English walnut) in the corner of the garden where its toxicity (Juglones) affects nothing. It was grown from seed about 12 years ago and it flowered for the first time two years ago, when we cropped 2 walnuts. Last year there were a few more, but this year it is currently looking like it will be a good crop. (We will forget about the squirrels for now.) Of course, it only takes a frost and all could be lost for the year. Walnuts are extremely vulnerable to frosts and tend to flower just as the last of the frosts occur. Their pretty red-tinged leaves blacken and the flowers are knocked right off. Over the years, cultivars have been breed that come into leaf just that bit later and therefore tend to have more reliable crops. Broadview, Buccaneer and Rita are all fairly self-fertile and are recommended for the English climate and moderate sized garden.
But it is the Japanese and Chinese walnut species that have the most dramatic flowers and these tend to be grown in England only as part of specialist or national collections (e.g. Wimpole Hall in Cambridgeshire or Northwick Estate, Gloucestershire). They are certainly not grown for their nut crops, which are often sparse and small.
The Chinese walnut, J. Mandschurica, tends to be a spreading tree and has very long catkins, (~30cm) hanging down like chains, while the female flowers appear on spikes and have red sticky stigma.
Male catkins on Juglans Mandschurica
Female flowers on the Chinese walnut, Juglans Mandschurica
The Japanese walnut, J. ailanthifolia, is more upright, but still has an open form. Again the catkins are long and the flowers (and ultimately nuts) appear on spikes.
Japanese walnuts, Juglans ailanthifolia
My favourite is the so-called Heartnut, J. ailanthifolia var. cordiformis, which produces the most pretty, small, heart-shaped nuts.
Heartnut, Juglans ailanthifolia var. cordiformis
If you’ve not seen these flowers before, it might be worth give a walnut tree a close look right now.
And while you are at it, check out the money-faced leaf scars!
Monkey-faced leaf scars on walnut
Frogend dweller's Blog 
Monkey faced scars remind me of plant identification questions at college. The catkins on Juglans Mandschurica are wonderful, is that tree at Wimpole too?
Yeah, me too. Yes, the J. mandschurica pictured is in the pleasure grounds at Wimpole. It is still quite a small tree and has not yet managed to set nuts that make it all the way to autumn, but there are one or two other examples that have.
I feel very well educated after reading your post. I adore walnuts, thank you!
Those money-faced leaf scars have completely caught my attention! 🙂
They are striking and a great way to identify the tree in winter.
Pingback: Collections and hard graft | Frogend dweller's Blog