Sophora japonica datiana

Tree of the Week - Entry 4 - August 2026

Sophora japonica 'Datiana' - the pagoda tree that gave up flowering and kept the good looks

I'll be honest, this one's grown for its shape, not its flowers - and once you've seen that little umbrella head shrugging off a dry August, you understand why. 'Datiana' is a weeping, umbrella-headed cultivar of the Japanese pagoda tree, bred specifically to be flowerless and fruitless. The species itself is one of the latest trees to bloom in these islands, its pea-like white flowers appearing as late as August and lasting a month or more - and right now, if there's a straight Sophora japonica nearby, it's probably doing exactly that. 'Datiana' won't. It has traded the blossom for form: a gnarled, twisting, half-open crown that grows in a way the old garden writers would have called picturesque, and meant it as a compliment.

There's an old pagoda tree at Kew that has been there since 1760. It's on its side now, held together by decades of careful attention. Plants of the World Online, Royal Botanic Gardens, Kew, notes that "Collectively these original trees are known as Kew's 'Old Lions'." Trad's Diary, recounting a talk by Tony Kirkham on 250 years of Kew's trees and gardeners, describes them as "propped and botoxed-up as necessary." That one is a species tree, not 'Datiana', but it tells you something about the constitution of the genus. Trees and Shrubs Online, updating Bean's Trees and Shrubs Hardy in the British Isles, puts it plainly: "Pagoda Trees need maximum summer heat to thrive like this in the UK." High summer, then, is the right moment to think about this tree.

Beneath the soil

Here is the fact I like best about this tree, and it's one anyone can check for themselves on a young shoot: the new growth stays green for several years before it darkens to brown. Three to four years, sometimes longer. It's the surest way to identify a young pagoda tree even when it's leafless. Look at a resting bud in winter too - small, woolly, black, sitting half-hidden inside the base of the leaf scar rather than proud of it. An easily-missed detail, and a good one.

Now the underground story, because it's genuinely odd for a member of the pea family. Most legumes form partnerships with rhizobia, the nitrogen-fixing bacteria that live in root nodules and let the plant make its own fertiliser. Sophora japonica does not do this. The genus has been reclassified as Styphnolobium japonicum - you'll see both names on stock lists depending on which side of that reclassification a grower sits - and the whole reason for the name change is precisely that Styphnolobium lacks the ability to form symbioses with rhizobia. It's a legume that never learned the family trick of fixing its own nitrogen. It still forms the ordinary mycorrhizal partnerships that most trees rely on for phosphorus and water uptake, but it earns no nitrogen subsidy from the soil bacteria that its cousins take for granted.

'Datiana' arrives as a grafted standard - the crown budded onto rootstock at head height, which is what gives it that neat weeping lollipop shape from a young age rather than something that has to be coaxed and trained over decades. The head itself stays a modest 2 to 4 metres wide. Formative pruning on the species is best done in full dormancy: it bleeds sap heavily if cut in spring, so any shaping belongs to autumn or deep winter, not to April.

Practical use

'Datiana' earns its keep in exactly the situations a full-size pagoda tree cannot fill. A courtyard, a gravel garden, a large container on a terrace, or as a single dramatic anchor in a small plot where a spreading canopy tree would swamp everything. Because it is flowerless and fruitless, there is no mess to sweep up and nothing for children or pets to find on the ground. That is useful where the ornamental form matters most - though it does mean bees get nothing from this particular selection, unlike the species. The crown stays fairly open and dappled rather than densely shading, which means underplanting has more light to work with than it would beneath a denser small tree.

Care and mistakes

Do:

• Plant in full sun on well-drained ground.
• Stake it properly at planting - a grafted standard with a dense, wind-catching head is more top-heavy than its slender trunk suggests.
• Prune in autumn or full dormancy only.
• Choose the final position with care before planting; it resents being moved once established.

Don't:

• Let it sit in wet ground - it dislikes waterlogging far more than it minds going dry.
• Prune in spring. This is the mistake most often made: tidying a weeping head in April and then wondering why it's weeping sap as well as branches.
• Expect it to fill out quickly in the first couple of seasons after transplanting - like most Sophora, it settles slowly.

Context and companions

Underplant it with things that enjoy the same dry, well-drained conditions rather than fighting them. Mediterranean-leaning planting sits naturally beneath that light, high canopy - ornamental grasses, drought-tolerant perennials, a gravel scheme. The roots are shallow and far-reaching but don't run, so it tolerates being planted near paving without much fuss, and it shrugs off road salt, which makes it worth considering for gardens close to a road. In a Surrey summer like this one, when it's easy to see which plants have coped and which have sulked, that tolerance counts for something.

Questions people actually ask

The question that comes up most reliably in August is: why isn't mine flowering, when the one down the road is covered in white blooms? Because 'Datiana' has been selected specifically not to flower or fruit. It is a different tree from the species-type Sophora japonica, bought for its weeping shape rather than its blossom. If the flower is what someone is after, the species tree is the one to plant - but they will need space, patience, and a warm wall or an open sunny position to get the best of it. Trees and Shrubs Online is right that maximum summer heat is what drives a good display in this country.

People sometimes ask whether 'Datiana' is the same as the weeping pagoda tree they've seen elsewhere. Largely yes in spirit - there is also a cultivar called 'Pendula', which rarely produces flowers rather than never doing so. 'Datiana' is a distinct and more consistently flowerless and fruitless selection. The two are easy to confuse by name, but the habit of 'Datiana' is the more reliably tidy of the two.

And yes, people ask whether they can prune it whenever they like. They cannot. Autumn or full dormancy only, for the sap-bleeding reason above. It is one of those rules that sounds fussy until the first time someone ignores it.

If 'Datiana' has caught your attention, come and see it in person at Cedar Nursery in Cobham, Surrey. Our team is on hand to help you find the right position for it, talk through staking and establishment, and point you towards the companions that will make the most of that light, open canopy.

Come and stand under it. Cedar Nursery, Cobham, Surrey.