Mahonia Species

• Mahonia is an evergreen genus with several similar looking species. The all have spiny holly-like leaves and clusters of yellow flowers. Mahonia nervosa has long leaves, Mahonia aquifolium (Oregon Grape) has wider and shinier leaves and Mahonia repens has a roundish matte green leaf. All of these are cool weather varieties. Some species more common to warmer climates are Mahonia trifoliolata, which has a trio of narrow pointed leaves, and Mahonia lomariifolia, which has more leaflets along its stem than most. All have yellow flower clusters that form out of the plant's crown, giving way to edible berries that are nearly always blue.
  
  

Berberis Species and Varieties

• Berberis (Barberry) is a close relation to Mahonia; in fact, some would argue that both Mahonia and Berberis should all fall under the Berberis name. Some barberries are deciduous, but a few are evergreen. The evergreen varieties almost always have small holly-like leaves. William Penn has leaves about an inch long, and Julian has much smaller leaves. Each is evergreen and bears yellow to orangey-yellow flowers along the underside of the stickery stems. The stems and roots have been used historically for dyes.
  
  

Thunbergia

• Thunbergia, or Black-Eyed Susan Vine, is a vine with evergreen arrowhead-like leaves. In cooler climates it will act as a perennial and in warmer climates as an evergreen. It has bright yellow, five-petalled flowers with deep-throated dark centers. The flowers aren't exclusively yellow; they can also be orange, white, red, or reddish pink. They are used as a climbing vine or an addition to a mixed hanging basket.
  
  

Epimedium

• Epimedium is often grown for the pretty leaves rather than the flowers. Often the leaves are a matte-green color with a red blush, and they are especially tolerant of the shade conditions that other plants find difficult. The small yellow flowers of some varieties are reminiscent of daffodils, while others look spidery and have spurs. It forms a mat about 12 inches tall and grows well in forest settings. It is used medicinally for a number of ailments.