Mahonia aquifolium, or Oregon grape, is an ornamental shrub native to the Pacific Northwest prized for its sweeping branches with holly-like leaves and its grape-like berries. It contributes structure, texture and color to home gardens throughout North America. It is very easy to grow. So easy, in fact, that it often quickly outgrows its location and needs to be transplanted. Sometimes, when not planted in the right light or soil, it languishes and needs to be moved. Mahonia is easy to transplant and once given a more suitable location, will thrive very quickly.
Choose a spot suitable for your mahonia. It naturally grows on forest edges, so choose a mostly shady location with dappled sunlight or morning and evening sun. The farther north, or the colder your climate, the more sun you can give it—but never full afternoon sun. In the South and very hot locations, mahonia will require something closer to full shade.
Dig a hole about 12 inches deep and about as wide as the branch-spread of the mahonia you are transplanting. Set the soil aside on a plastic sheet.
Improve the soil in the bottom of the hole by adding and mixing in about one-third compost.
Prune the branches of your mahonia back about one-third or one-half. This will ensure that the canopy is not too big for the root system to support.
Dig a circle around your plant with a sharp spade a little bigger in diameter than the pruned canopy, cutting through the roots the depth of the shovel.
Rock the shovel gently back and forth around the sides of the root ball, working underneath the plant as you go. Mahonia is shallow-rooted and should not be too hard to unearth. Cut through any roots which get in the way with the shovel or with the pruners. Preserve as much of the soil around the root ball as you can.
Move the plant, with its root ball intact, to its new location. If the root ball is loose, work burlap or an old cotton shirt under the root ball and tie it around the base of the plant. There is no need to remove the material once the root ball is in its new location. It will biodegrade soon.
Tamp the plant gently in its new location, adding amended soil around and under it so that the hole is filled and the top of the root ball is even with, or 1 or 2 inches above, soil level.
Soak the root ball to settle it in its hole by slowly soaking the rootball with 3 or 4 gallons of water, a few of which have been enriched with a plant starter formula, according to label instructions.
Continue to water the transplanted mahonia throughout the first season to help its roots become established.