Which tree has green balls? Sort it by the size of the ball

Big green balls: Osage orange

A green ball the size of a softball or a grapefruit, deeply wrinkled and heavy, is an Osage orange, also called hedge apple. Only female trees bear it, from September to October, and its bitter milky juice can irritate skin. The tree has sharp thorns beside each leaf and orange-brown bark, and it was planted as hedgerows across the Midwest and South. The Osage orange profile covers the tree in full, including male trees that never fruit.

Golf-ball to tennis-ball size: walnuts, pecans and oak galls

Black walnut. A smooth green ball 1 to 3 inches across, hanging singly or in pairs from a tree with very long compound leaves, is almost always a black walnut. The NC State profile describes a fleshy yellow-green husk that does not split, around a brown to black nut 1 to 3 inches across, with nuts developing by October. The husk heavily stains skin and clothing, a quick confirmation after you pick one up. The leaves are 12 to 24 inches long with 15 to 23 finely toothed leaflets, and they emerge late and drop early. NC State also notes that the tree's juglone inhibits some plants under its dripline, such as tomatoes and azaleas. The walnut page separates black walnut, butternut and English walnut.

Pecan and hickories. A green ball with a seam that splits open when ripe is a hickory or pecan. The NC State pecan profile gives a green husk that dries brown and splits into four sections when ripe in fall, around an oval nut 1 to 3 inches long, on leaves with 9 to 17 leaflets. Walnut husks stay closed; hickory and pecan husks open. See the hickory page for the other species.

Oak apple galls. If the green ball is stuck to an oak leaf or bud rather than hanging from a stalk, it is not a fruit at all. Ohio State University Extension describes two common types on oaks in the red oak group, both 1/2 to 2 inches across and green while the gall wasp inside develops:

• the spongy oak apple gall, light green and smooth, with spongy, juicy tissue like apple flesh, made by Amphibolips confluenta on scarlet, red and black oaks;
• the large empty oak apple gall, light green with purplish-red bumps, hollow inside with white fibers radiating from the center, on scarlet and red oaks.

Both turn light brown and dry once the new wasp emerges, and many end up on the ground under the tree.

Marble-size balls: bald cypress, chinaberry and cherry laurel

Bald cypress. A round green ball on a conifer with soft, feathery needles, by a pond, river or swamp, is a bald cypress cone. The NC State profile gives female cones 3/4 to 1 inch across, purplish green maturing to brown in October, with thick, irregular scales, on a tree whose flat needles, 1/4 to 3/4 inch long, lie in two flat rows. Bald cypress drops its needles in fall, and trees growing in or near water raise knobby "knees" from their roots. It grows wild from Delaware to Florida and west to Texas. This is the usual answer to "cypress tree with green balls".

Chinaberry. A tree with lacy, fern-like leaves and clusters of round, yellow-green balls is a chinaberry. The NC State profile describes twice-divided leaves 12 to 24 inches long with toothed, pointed leaflets, fragrant lilac flowers in spring, and wrinkled, sticky fruit 0.4 to 0.5 inch across with a hard, marble-like seed. The fruit turns yellow and hangs on the bare tree through fall, winter and into spring. Chinaberry is native from India through China to Australia; NC State reports it as an invasive species in North Carolina, and says the NC Invasive Plant Council and many southern states list it. NC State rates it as having medium-severity poison characteristics, with the fruit, leaves, bark and seeds among the toxic parts.

Carolina cherry laurel. An evergreen with glossy leaves and small green fruit that later turns black is often a Carolina cherry laurel, common in Southeastern yards and woods edges. The NC State profile describes fruits under 1 inch that are green and mature to lustrous dark black from September to October, on a tree up to 35 feet with smooth-edged leaves 2 to 3 inches long. Crush a leaf: it smells of maraschino cherry. NC State lists the leaves, seeds, stems and green fruit as cyanogenic.

Pea-size balls: linden and camphor tree

Linden or basswood. Small, hard, downy balls about the size of a pea, hanging in clusters beneath a long, pale leafy wing, are linden fruit. The NC State basswood profile explains that each nutlet hangs from a stalk attached to a bract that acts as a wing in the wind, with fruit from July to August in North Carolina. The leaves are heart-shaped and lopsided at the base. In Britain the same genus is called lime; the linden page covers American basswood and the European limes.

Camphor tree. In Florida, an evergreen with shiny leaves and clusters of small fruit ripening black is often a camphor tree. UF/IFAS Gardening Solutions says crushing a leaf or peeling a twig releases a camphor odor, and that birds eat the shiny black berries and spread the seeds. The University of Florida's assessment lists camphor tree as invasive in North and Central Florida and as a caution species in South Florida. UF also warns not to confuse it with native red bay, which smells similar.

Spiky or fuzzy green balls, and UK readers

If the green ball is covered in points or soft fuzz, it is the summer stage of a tree on the spiky balls guide: sweetgum (beaked points, star-shaped leaves), American sycamore or London plane (fuzzy, on a long stalk), horse chestnut or buckeye (leathery, prickly husk), or chestnut (needle-sharp bur). Those balls turn brown in fall.

In Britain and Ireland, four common trees carry green balls: a horse chestnut with its prickly conkers, a London plane with its hanging fuzzy balls, a lime with its pea-size nutlets under a wing, and a walnut in its green husk. If the ball is black instead of green, try the tree with black berries guide.

When a photo helps

Green balls are often high in the crown. A photo that shows one ball and the leaves around it, or a fallen ball next to a fallen leaf, gives the best lead. Tree Identifier names a tree from one photo, and black walnut, bald cypress, American sycamore and sweetgum are in the app's Collection. The app does not show a confidence score or a list of look-alikes, so check the result against the size table above. Tree Identifier's follow-up chat can answer questions such as whether a gall harms an oak; for anything about eating fruit or nuts, ask a local expert.