Sessile oak ( Quercus petraea ) is a large, long-lived deciduous tree native to most of Europe. It is the national tree of Ireland. It prefers moist, fertile well-drained soils but is adaptable to poorer, drier soils and does well in clay. It prefers an acid pH but is adaptable to neutral and even alkaline soils. The acorns have no stalks (sessile) and develop from the stem in clusters. It has a broad rounded crown and is resistant to mildew. It is a host plant for the larvae of the Imperial moth ( Eacles imperialis ) , as well as numerous butterflies, including Banded hairstreak ( Satyrium calanus ) , Edward's hairstreak ( Satyrium edwardsii ) , Gray hairstreak ( Strymon melinus ) , White-m hairstreak ( Parrhasius malbum ) , Horace's duskywing ( Erynnis horatius ) , and Juvenalis duskywing ( Erynnis juvenalis ) . Sessile oak can be difficult to find in this country.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt)
Soil pH
Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage
Available space
more than 60 feet
NC region
Mountains; Piedmont
Mature size
Height: 60 ft. 0 in. - 80 ft. 0 in. | Width: 60 ft. 0 in. - 80 ft. 0 in.
Growth rate
Medium
Maintenance
Medium
Canopy layer
1 - Canopy (>40 ft)
Form & Appearance
Habit / form
Rounded
Texture
Medium
Foliage
Deciduous
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Obovate
Leaf margin
Lobed; Undulate
Leaf size
3-6 inches long, < 1 inch wide
Hairs present
Yes
Leaf detail
3-5 inch leaves are glossy green above and pale and smooth to pubescent underneath with 4-6 pairs of rounded lobes.
Fall color
Gold/Yellow
Flower color
Gold/Yellow
Flower form
Catkin; Insignificant
Flower detail
The flowers form greenish-yellow drooping catkins. Flowering and leafing sprout together..
Bloom time
Spring
Fruit color
Brown/Copper
Fruit type
Nut
Fruit size
1-3 inches long, < 1 inch wide
Fruit detail
1.2-inch oval acorns are stalkless and in clusters with a cap covering about 1/3 of the nut. They mature the first year.
Bark color
Dark Gray
Bark detail
The bark is smooth and gray, later deeply fissured.
Stem color
Brown/Copper; Gray/Silver
Stem detail
Twigs grey-brown, shiny, hairless, angled, with small tawny lenticels
Wildlife & Ecology
Native status
Non-native
Origin
Europe to Northern Iran
Wildlife value
Many birds and mammals eat the acorns. Oak trees support a wide variety of Lepidopteran. You may see Imperial Moth (Eacles imperialis) larvae which have one brood per season and appear from April-October in the south. Adult Imperial Moths do not feed. Banded Hairstreak (Satyrium calanus), which have one flight from June-August everywhere but Florida where they emerge April-May. Edward's Hairstreak (Satyrium edwardsii), has one flight from May-July in the south and June-July in the north. Gray Hairstreak (Strymon melinus), has three to four flights in the south from February-November and two flights in the north from May-September. White-M Hairstreak (Parrhasius m-album) has three broods in the north from February-October. Horace’s Duskywing (Erynnis horatius) has three broods in Texas and the deep south from January-November, and two broods in the north from April-September. Juvenal’s Duskywing (Erynnis juvenalis) has one brood from April-June, appearing as early as January in Florida.
Attracts
Butterflies; Moths; Pollinators
Play value
Wildlife Food Source
Food & Medicine
Edible parts
Nuts
Harvest time
Fall
Fruit type
Nut
Edibility
Acorns (nuts) are edible after tannins are leached or boiled out.