Judas Tree
Cercis siliquastrum
A warm wall at its back suits it best, and summer is the only safe season to put a blade to it.
- Type
- Tree · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green · Silver and gray
- Flower color
- Pink
- Sunlight
- Full sun, and best of all with a south-facing wall behind it.
- Watering
- Regular water until it is settled, after which it looks after itself in dry weather.
- Feeding
- Compost mulch while young; nothing once it is established.
- Frost tolerant
- Yes
- Flowering
- April
- Pruning
- Prune in summer once flowering is over, and at no other time.
- Overwintering
- Hardy in mild gardens; shelter young trees where winters bite.
- Apr–May Flowering
- May–Jun Bud Break
- Jun–Oct Growing
- Oct–Dec Leaf Fall
- Jan–Apr Leaf Fall
- Plant spacing
- 16 ft 5 in
- In-row spacing
- 16 ft 5 in
- Between rows
- 20 ft 6 in
- Square-foot density
- Not suited to SFG
- Root system
- Woody, with a taproot it keeps
- Working depth
- 24 in–5 ft
- Can reach
- 10 ft down where the soil allows
- Spread
- 25–41 ft across, about 1.5–2.5× the width of the plant
It anchors downwards as well as sideways, which is what lets it stand in a gale and what makes it hate being moved. Plant it small: past a few years in the ground a taprooted tree transplants badly, and often not at all.
A taproot that makes it very hard to move once it is established, which is why redbuds are sold small and planted young. It also means the tree stands drought better than its thin twigs suggest.
The habit is Judas Tree’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Hoverfly SyrphidaeHunts Scale insects
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Ladybird (lady beetle) CoccinellidaeHunts Scale insects
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
Green-leaved trees, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com