|Chinese witch hazel (Hamamelis mollis) blooming in January in my Seattle garden.|
Botanically speaking, there are two types of witch hazels commonly planted in our area: H. mollis, the Chinese witch hazel, and H. x intermedia, which is a cross between H. mollis and H. japonica. The Chinese witch hazel, which you see pictured above, has clear yellow flowers with reddish sepals. The H. x intermedia group features several named varieties with distinctive characteristics. 'Diane,' for example, has dark red flowers that fade to orange; 'Arnold Promise' has bright yellow flowers; 'Jelena' has coppery orange flowers.
All varieties of witch hazels put on another show in fall. Depending on the cultivar, fall color ranges from yellow, through red, orange, purple and scarlet. Before selecting one for your garden, be sure to do two things: look up the cultivars in the Sunset Western Garden Book for a full description of flower and fall color; and shop for your tree now, when they are in bloom, to be sure you get the color and fragrance you want.
I also recommend that you visit the Winter Garden at the Washington Park Arboretum, where you can see mature specimens in bloom now.
Witch hazel bark and leaves have long been used medicinally, which you can read more about here.
For small gardens, witch hazels are winners. They provide year around beauty and color. They don't get too big - rarely over 15'. (I have two, planted 8 years ago, and the tallest is just over 6'.) They have a pleasing vase shape that requires little, if any, pruning. They don't have any major pest or disease problems that I am aware of. They just offer lots of beauty in a small package.