(Canada Thistle)

Canada thistle is a fierce and aggressive weed foe. Impossibly extensive, deep root systems make this one of the toughest weeds to eradicate from garden spaces. It's small, purplish, brush-like flower heads produce loads of puffy airborne seeds that float away to colonize new space, and its prickly foliage is painful to the touch. Despite the common name, Canada thistle, this species was introduced to North America from Eurasia. Its remarkable tolerance to many growing conditions means it can be...

(Ellen Danica Grape Ivy, Grape Ivy)

Given its name for its black fruits, grape ivy selection 'Ellen Danica' boasts handsomely toothed leaves that are deep glossy green upon hairy stems. A modest, climbing or rambling evergreen vine, it hails from Central and South America and the Caribbean Basin.

The leaves are trifoliate, each comprised of three leaflets that are rhombus-shaped with sparse teeth on their edges. Light bronze-green when young, the leaves mature to a deeper green and bear red hairs on their underside. In summer,...

(Arizona Grape Ivy, Ivy Treebine, Possum Grape, Sorrel Vine)

Very fast-growing and displaying attractive teethed green leaves that fall away in winter, sorrel vine is a versatile vine or groundcover. Native to the southern United States and adjacent parts of northern Mexico, it bears tendrils opposite the leaves that will clasp onto any surface that isn't glass-smooth.

The leathery, succulent green leaves are variable in shape. Usually they're three-lobed but occasional deltoid-shaped blades occur with or without lobes, but always with coarse teeth. Tiny...

(Devil's Backbone, Veldt Grape, Winged Treebine)

Here's a succulent tropical vine that has more interesting stems than leaves. Winged treebine hails from tropical Africa, the Arabian Peninsula and eastern India. Odd-looking and generally leafless, its primary feature are thick, jointed, four-angled green stems.

The leaves, which aren't all that frequent, occur opposite tendrils at nodes on the winged stems. Each leaf is oval or three-lobed with coarse teeth and a fleshy texture. In summer, tiny clusters of green-yellow flowers appear, followed...

(Marine Ivy, Mexican Grape Ivy, Mexican Sorrelvine)

Known as marine ivy or Mexican sorrelvine, this mostly herbaceous vine that grows from a woody stem base hails from arid northern Mexico. Naturally inhabiting salt marshes, chaparral and open woodlands, both its leaves and fruits provide ornamentation to the dry garden.

Simple or forked tendrils help the stems clasp onto trees or climb over shrubs. Evergreen only when frosts don't occur, marine ivy's leaves are smooth and dark green and dry green and papery thin. Typically each leathery and fleshy...

(Common Gum Rockrose)

A relatively large rockrose that is also notable for its aromatic foliage and large flowers, this native of Southwest Europe and Northwest Africa bears its palm-sized white blooms in late spring and early summer. It may produce a few blossoms at other seasons. Each of the five crinkled petals has a maroon blotch at its base. A ruff of yellow stamens adorns the flower's center. The lance-shaped, fragrant, sticky leaves are dark green above and gray beneath. They are borne on erect stems that eventually...

(Common Gum Rockrose, Frank Birch Rockrose)

A relatively large rockrose that is also notable for its aromatic foliage and palm-sized white flowers, Cistus ladanifer is native to Southwest Europe and Northwest Africa. The flowers of the cultivar 'Frank Birch' lack the purple basal blotches typical of the species. The crinkled, five-petaled blooms appear in late spring and early summer, and sporadically at other seasons. A ruff of yellow stamens adorns each flower's center. The lance-shaped, fragrant, sticky leaves are dark green above...

(Sageleaf Rockrose, White Rockrose)

This rockrose isn’t a true rose but a drought- adapted, large-flowered shrub from the Old World. It is found along the coast of the Mediterranean Sea and further inland where winters are mild and rainy followed by a long, dry summer. The leaves are small, rough and gray-green, typical of many plants adapted to drought. They are are rich in potent oils once extracted as a substitute for the ancient perfumer’s ambergris.

These evergreen shrubs do their growing during the moist winter months. In...

(Rockrose)

Rockrose is a hardy, evergreen shrub. It is a natural hybrid between Cistus ladanifer and Cistus populifolius, both native to the Mediterranean region. Shiny, sticky leaves are lance-shaped, opposite on the stem and have smooth to wavy margins. The lovely, papery, abundant, summer flowers are solitary and open for one day. They are roundish, flat, white with a red tint, have a center of bright gold stamens and reminiscent of wild roses. The stems and foliage have a pleasant, resinous...