Oak
Quercus
A tree measured in decades rather than seasons — twenty meters of canopy, and it needs every bit of the room.
- Type
- Tree · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Sunlight
- Full sun, with enough open ground for a broad canopy.
- Watering
- Water while young; a settled oak finds its own water in dry years.
- Feeding
- All-purpose balanced
- Frost tolerant
- Yes
- Pruning
- Light winter cuts only, and never top a mature tree.
- Mar–Nov Bud Break
- Nov–Dec Leaf Fall
- Jan–Mar Leaf Fall
- Plant spacing
- 39 ft 4 in
- In-row spacing
- 39 ft 4 in
- Between rows
- 49 ft 3 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
- 59–98 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.
The habit is Oak’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.
- Leafrollers Oak tortrix moth caterpillars stripping foliage in late spring
- Powdery mildew Oak powdery mildew on the young leaves
- Oak processionary moth — a notifiable pest, and one to report rather than handle
- Gall wasps, whose galls are cosmetic and need no treatment
- Acute oak decline, showing as dark weeping bark — get professional advice
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Bats ChiropteraHunts Leafrollers
A single bat takes hundreds of moths and mosquitoes in a night, and the moths are the parents of your cutworms, corn earworms and hornworms. Put up a bat box on a warm south wall, leave a night-scented corner unlit, and never spray after dark.
- Parasitic wasps Braconidae & TrichogrammaHunts Leafrollers
Tiny, stingless wasps that lay eggs in or on caterpillars, aphids, and moth eggs — the white cocoons riding a hornworm are their calling card, so leave that caterpillar be. Umbel flowers with shallow nectar keep the adults fuelled.
Green-leaved trees, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com