Juglans microcarpa
Texas Walnut
a perennial woody deciduous member of the Juglans genus in the family Juglandaceae.
Taxonomy and growth
- Family
- Juglandaceae
- Genus
- Juglans
- Life cycle
- perennial
- Foliage
- deciduous
- Woodiness
- woody
- Height
- 10 m
- Spread
- 10 m
- Fertility
- Self fertile, Wind
- Flower type
- monoecious
- Pollinators
- Wind
Uses
Edible uses
This section contains historical Plants For A Future notes marked noncommercial.
Seed - raw. The seed is sweet and oily but it is rather small and has a thick shell[9][14][2][8][12]. The seed is the smallest of this genus[17]. An edible oil is obtained from the seed, it tends to go rancid quickly.
- Product or use
- Oil
- Plant part
- Seed
Material uses
This section contains historical Plants For A Future notes marked noncommercial.
Sometimes used as a rootstock[8]. Plants produce chemicals which can inhibit the growth of other plants. These chemicals are dissolved out of the leaves when it rains and are washed down to the ground below, reducing the growth of plants under the tree[7][10][6]. The roots of many members of this genus produce substances that are toxic to many plant species, especially apples (Malus species), members of the Ericaceae, Potentilla spp and the white pines (certain Pinus spp.)[11]. Wood - heavy, hard, not strong. It makes a beautiful veneer and has been very over-exploited in the wild for this purpose[17]. It is also used in cabinet making, furniture etc[17][5].
- Product or use
- Herbicide
- Product or use
- Wood
Ecology and functions
- Ecosystem niche
- Canopy
Environment
- Range
- South-western N. America - Texas to Mexico.
- Light
- full sun
- Shade tolerance
- no shade
- Water
- moderate
- Hardiness
- Zone 6+
- Soil textures
- sandy, loamy, clay
- Soil pH
- acid, neutral, alkaline
- Drainage
- well drained
- Tolerances
- drought
- Tolerates Nutritionally Poor Soil
- No
- Drought
- tolerant
Propagation
This section contains historical Plants For A Future notes marked noncommercial.
The seed is best sown as soon as it is ripe in individual deep pots in a cold frame[16]. You need to protect it from mice, birds, squirrels etc. The seed usually germinates in late winter or the spring. Plant out the seedlings into their permanent positions in early summer and give some protection from the cold for their first winter or two. The seed can also be stored in cool moist conditions (such s the salad compartment of a fridge) over the winter and sown in early spring but it may then require a period of cold stratification before it will germinate[15][16][4].
Cultivation
This section contains historical Plants For A Future notes marked noncommercial.
Requires a deep well-drained loam and a sunny position sheltered from strong winds[1][3]. Prefers a slightly alkaline soil[11]. This species often experiences drought in its native range[13]. Plants produce a deep taproot and they are intolerant of root disturbance[1][3]. Seedlings should be planted out into their permanent positions as soon as possible and given some protection for their first winter or two since they are somewhat tender when young[1][3]. Flower initiation depends upon suitable conditions in the previous summer[11]. The flowers and young growths can be destroyed by even short periods down to -2°c, but fortunately plants are usually late coming into leaf[11]. Any pruning should only be carried out in late summer to early autumn or when the plant is fully dormant otherwise wounds will bleed profusely and this will severely weaken the tree[11]. Trees have a dense canopy which tends to reduce plant growth below them. We have no specific information for this species, but the roots of several members of this genus produce substances that are toxic to many plant species, especially apples (Malus species), members of the Ericaceae, Potentilla spp and the white pines (certain Pinus spp.)[11]. The leaves of many species also secrete substances that have an inhibitory affect on plants growing underneath them. All in all this is not a very good companion plant[K]. Closely related to J. major, and hybridizes with that species where their ranges overlap[13].
References
F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00
Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00
Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981-00-00
Dirr. M. A. and Heuser. M. W. The Reference Manual of Woody Plant Propagation. Athens Ga. Varsity Press 1987-00-00 ISBN 0942375009
Vines. R. A. Trees of Central Texas. University of Texas Press 1987-00-00 ISBN 0-292-78958-3
McPherson. A. and S. Wild Food Plants of Indiana. Indiana University Press 1977-00-00 ISBN 0-253-28925-4
Philbrick H. and Gregg R. B. Companion Plants. Watkins 1979-00-00
Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9
Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6
Riotte. L. Companion Planting for Successful Gardening. Garden Way, Vermont, USA. 1978-00-00 ISBN 0-88266-064-0
Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5
Vines. R.A. Trees of North Texas University of Texas Press. 1982-00-00 ISBN 0292780206
Elias. T. The Complete Trees of N. America. Field Guide and Natural History. Van Nostrand Reinhold Co. 1980-00-00 ISBN 0442238622
Elias. T. and Dykeman. P. A Field Guide to N. American Edible Wild Plants. Van Nostrand Reinhold 1982-00-00 ISBN 0442222009
Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948-00-00
McMillan-Browse. P. Hardy Woody Plants from Seed. Grower Books 1985-00-00 ISBN 0-901361-21-6
Sargent. C. S. Manual of the Trees of N. America. Dover Publications Inc. New York. 1965-00-00 ISBN 0-486-20278-X