Carya illinoinensis

Common Name Pecan
Family Juglandaceae
USDA hardiness 5-9
Known Hazards None known
Habitats Rich moist soils of bottomlands[229], especially along the sides of streams[235].
Range Southern N. America - mainly along the Mississippi river valley.
Edibility Rating  
Medicinal Rating  
Fully Hardy Moist Soil Full sun

Bloom Color: Yellow. Main Bloom Time: Early spring, Late spring, Mid spring. Form: Oval, Rounded.
Carya illinoinensis Pecan
Carya illinoinensis Pecan
Physical Characteristics
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Carya illinoinensis is a deciduous Tree growing to 50 m (164ft 1in) at a medium rate.
It is hardy to zone (UK) 5. It is in leaf 10-Jun It is in flower from Apr to May, and the seeds ripen in October. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Wind.The plant is self-fertile.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils and can grow in very acid and very alkaline soils.
It cannot grow in the shade. It prefers moist soil.


C. pecan. Juglans illinoensis.
Woodland Garden Canopy;
Edible Uses
Edible Parts: Oil;  Seed.
Edible Uses: Milk;  Oil;  Tea.

Seed - raw or cooked[46, 82]. Sweet and delicious, they make an excellent dessert and are also often added to ice cream, used in cakes, bread etc[149, 183]. A milk can be made from the seed and is used to thicken soups, season corn cakes, hominy etc[183]. The seed is up to 4cm long and is produced in clusters of 3 -11[82, 229]. The seed ripens in late autumn and, when stored in its shell in a cool place, will keep for at least 6 months[K]. An edible oil is obtained from the seed[177, 183]. The leaves are said to be used as a tea[177, 183].
Medicinal Uses

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Astringent;  Parasiticide;  TB.

The bark and leaves are astringent[227]. A decoction of the bark has been used to treat TB[257]. The pulverized leaves have been rubbed on the skin to treat ringworm[257].
Other Uses
Fuel;  Oil;  Parasiticide;  Wood.

Wood - coarse-grained, hard, heavy, brittle, not strong. It weighs 45 lb. per cubic foot. It is not as valuable a timber as other members of this genus and is used mainly for fuel and occasionally to make wagons and agricultural implements[46, 82, 227, 235].
Cultivation details
Landscape Uses:Aggressive surface roots possible. Prefers a deep moisture-retentive loam in a sunny sheltered position, requiring a good summer for best development[1, 63, 137, 200]. Tolerates a pH in the range 4.5 to 8.3. Trees are fairly fast growing[200]. Trees do not grow very well in Britain, requiring hotter summers than are normally experienced here in order to fruit and fully ripen their wood[200]. However, a tree at Cambridge botanical gardens was 20 metres tall in 1985. Trees are said to be hardy to about -12°c, the same report also says that they are hardy to zone 5[200], which would experience considerably lower temperatures than this. Trees are probably much hardier when grown in areas with hot summers. In the wild, trees grow best in areas where summer temperatures average 24 - 30°c and the humidity is high[229]. Often cultivated for its edible seed, there are some named varieties[183]. Trees come into bearing when about 20 years old, the best period of production being between the ages of 75 to 225 years old[229]. Mature trees regularly give yields of 225 kilos, whilst yields of 450 kilos have been recorded[229]. A number of cultivars have been developed in N. America that succeed quite far north in that country[200]. These cultivars include:- 'Carlson 3'. Early maturing, it is being trialled in Canada[183]. 'Devore'. An early fruiting form with small nuts that have an excellent flavour[183]. 'Gibson'. Precocious, protandrous, the nuts are of medium size with a good flavour[183]. 'Green Island'. Amongst the hardiest of cultivars, it has been selected for nut size, flavour and productivity[183]. 'Mullahy'. Hardy, precocious and very productive, it has ripened in Ontario[183]. Nuts are fairly large with an excellent flavour. 'Voiles 2'. Usually ripens as far north as Ontario and New York[183]. The wind-blown pollen is a significant cause of hay fever in the Unitd States[274]. This species is the State Tree of Texas[274]. Plants are strongly tap-rooted and should be planted in their permanent positions as soon as possible[1, 137]. Sowing in situ would be the best method so long as the seed could be protected from mice[1, 200]. Trees are late coming into leaf (usually late May to June) and lose their leaves early in the autumn (usually in October)[137]. During this time 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[137]. Plants in this genus are notably resistant to honey fungus[200]. Most species in this genus have quite a wide range of distribution and, in order to find trees more suited to this country, seed from the most appropriate provenances should be sought[137]. Most trees growing in Britain at present tend to only produce good seed after hot summers[137]. Trees are self-fertile but larger crops of better quality seeds are produced if cross-pollination takes place[229]. Special Features:North American native, Inconspicuous flowers or blooms.
Seed - requires a period of cold stratification. It is best sown in a cold frame as soon as it is ripe[78]. Stored seed should be kept moist (but not wet) prior to sowing and should be sown in a cold frame as soon as possible[78]. 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 them some protection from the cold for at least the first winter[78, K]. 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[200] (a plastic bottle with the top and bottom removed and a wire mesh top fitted to keep the mice out is ideal)


Additional information for Pecan