Mesquite

Prosopis glandulosa

also called honey mesquite

The shade tree of the desert Southwest: lacy foliage, crooked sculptural trunks, filtered light a patio can live under, and roots that found water where nothing else could.

Light Full sun
Water Very low; deep soaks a few times a summer beat any schedule of sprinkling
Hardiness Hardy
USDA zones 7a–11a
Height 6–10 m
Spread 29 ft 6 in
Spacing 6–9 m
Sow depth From a container tree, watered deep and rarely to send the roots down
Root depth 5–13 ft
Type
Tree · Perennial
Botanical family
Legume (pea & bean family)
Foliage color
Green
Sunlight
Full sun
Watering
Very low; deep soaks a few times a summer beat any schedule of sprinkling
Soil
Any drained desert soil; rich watered ground makes it rank
Feeding
Gentle all-organic
USDA zones
7a–11a
Frost tolerant
Yes
Plant out
at the last spring frost
Plant spacing
23 ft
In-row spacing
19 ft 8 in
Between rows
29 ft 6 in
Square-foot density
Not suited to SFG
Root system
Woody, with a taproot it keeps
Working depth
5–13 ft
Can reach
164 ft down where the soil allows
Spread
44–74 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.

Mesquite holds the record for the deepest roots ever recorded on a tree, found more than fifty metres down in a mine shaft. In a garden it means a tree that is never watered once established, and a tree that is never successfully moved.

Figures recorded for Mesquite itself. 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.

When
Ripe pods in midsummer, dry and straw-colored, straight from the branch.
What to look for
Pods rattle-dry, tan to reddish, and snap cleanly; sweet when chewed. Pods off the ground carry mold invisibly and are left there.
How to harvest
Pull pods from the tree on a dry day, oven-dry them crisp, and grind pods whole (seeds and all) in a strong blender, sifting out the hard bits. The flour is naturally sweet and gluten-free.
How often
One or two pickings; the tree needs nothing in return but restraint with the hose.
Storing the crop
Dried pods keep for months in a sealed bucket; the flour keeps best frozen. Prune for shape only in winter, wearing gloves that respect the thorns.
  • Generally trouble-free No notable pest or disease problems when grown in the right conditions — one of the easy ones.

The bean pods are an ancient staple, ground sweet and nutty into mesquite flour, and the wood is the barbecue smoke of Texas. Water it shallow and often and it grows fast, soft and shallow-rooted: the classic blown-over mesquite is an overwatered one.