Carya glabra is a highly polymorphic species. Tight-barked trees bearing large pear-shaped fruits are common along the Gulf Coast ( previously known as Carya. megacarpa, Carya leiodermis and Carya magnifloridana ). Trees with exfoliating bark, reddish petioles, and small, compressed, ellipsoid fruits that dehisce to the base (formerly Carya ovalis ) are more common at higher latitudes.
Carya glabra intergrades with Carya floridana, Carya pallida, and Carya texana, and it is reported to hybridize with the diploid Carya cordiformis ( as Carya × demareei Palmer).
The extreme northern ovalis form of the species also appears to hybridize with the typical glabra in areas of sympatry[].

Common Name: Sweet Pignut

General Information

Carya glabra is a deciduous tree that commonly grows around 24 - 27 metres tall, but can reach 37 metres with a trunk up to 90 - 120cm in diameter. The trunk is often forked[]..
The plant is harvested from the wild for local use as a food and source of materials. Sometimes cultivated for its edible seed, there are some named varieties[], the plant is also grown commercially for its timber, especially in central Europe[]. It is grown as an ornamental, where it is appreciated especially for the shade it supplies and the yellow colour of its leaves in autumn[]..
Carya glabra has a large stable population, an extensive range and there are no known major threats. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

, ,

Range

Eastern and central N. America - Wisconsin, Ontario and New Hampshire, south to Texas and Florida.

Habitat

Edge of bayous, deep flood plains, well-drained sandy soils, rolling hills and slopes, dry rocky soils, or thin soils on edge of granite outcrops; at elevations up to 800 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Other Uses Rating
Habit	Deciduous Tree
Height	30.00 m
Growth Rate	Slow
Pollinators	Wind
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Carya glabra grows in a humid climate with an average annual precipitation in the range 760 - 2,030mm, of which around 50 - 60% occurs during the growing season. Average snowfall varies from little to none in the south of its range to 2,540mm or more in the Appalachian mountains. Average annual temperatures can vary from 7°c in the north to 21°c in Florida. Average January temperature varies from -4° to 16°c and average July temperature varies from 21° - 27°c. Extremes of 46° and -30°c have been recorded within the range. The growing season varies by latitude and elevation from 140 to 300 days[]..
Prefers a deep moisture-retentive loam in a sunny sheltered position, requiring a good summer for best development[, , , ]. In its native habitat it is a moderately shade-tolerant canopy tree[]. Succeeds in drier soils than most members of this genus[]. Slow growing[].
Trees take 25 - 30 years before they commence bearing seeds and peak production does not begin until they are about 80 years old, but can continue for another 200 years or more[, ]. Trees thrive in cooler maritime climates, often bearing fruit[].
Trees with resprout from the stump and from the roots if they are cut down[].
Plants are strongly tap-rooted and should be planted in their permanent positions as soon as possible[, ]. Sowing in situ would be the best method so long as the seed could be protected from mice[, ].
Plants in this genus are notably resistant to honey fungus[].
Most species in this genus have quite a wide range of distribution and, in order to find trees more suited to a specific climate, seed from the most appropriate provenances should be sought[]. Most trees growing in Britain at present tend to only produce good seed after hot summers[].
Trees are self-fertile but larger crops of better quality seeds are produced if cross-pollination takes place[].

Edible Uses

Seed - raw or cooked[, , ]. Very variable in quality, some are sweet and pleasant whilst others are bitter and astringent[, , , , , ]. In general it is inferior to other hickories[, ]. The nut is rather small[], has a very thick shell and contains very little edible matter[, ]. The seed ripens in late autumn and, when stored in its shell in a cool place, will keep for at least 6 months[].

Sap - tapped in spring and used as a refreshing drink. A sweet flavour[].

Medicinal

None known

Agroforestry Uses:

Trees are late coming into leaf (usually in late spring to early summer) and they lose their leaves early in the autumn (usually in October)[]. Whilst in leaf they cast a heavy shade. These factors combine to make the trees eminently suitable for a mixed woodland planting with shrubs and other trees beneath them[].

Other Uses

Wood - hard, strong, tough, very flexible. It weighs 51lb per cubic foot[]. An excellent timber, it is used for tool handles, agricultural implements etc[, , ]. Sporting goods, agricultural implements, and tool handles are made from the wood, as well as specialty products such as shuttle blocks, mallets, and mauls[].
A very good fuel, burning well and giving off a lot of heat[, , ]. It makes a good charcoal.

Propagation

Seed - requires a period of cold stratification - seed given 3 months cold stratification had a 91% germination rate[]. Best sown in a cold frame as soon as it is ripe[]. Stored seed should be kept moist (but not wet) prior to sowing and should be sown in a cold frame as soon as possible[]. Where possible, sow 1 or 2 seeds only in each deep pot and thin to the best seedling. If you need to transplant the seedlings, then do this as soon as they are large enough to handle, once more using deep pots to accommodate the tap root. Put the plants into their permanent positions as soon as possible, preferably in their first summer, and give some protection from the cold for at least the first winter. Seed can also be sown in situ so long as protection is given from mice etc and the seed is given some protection from cold[] (a plastic bottle with the top and bottom removed and a wire mesh top fitted to keep the mice out is ideal)