Lewis' mock orange, also known as mockorange and by the scientific name Philadelphus lewisii, is the state flower of Idaho and was discovered by Merriweather Lewis. It features bright white flowers and is considered a hardy plant because it can tolerate a large variety of soil as well as grow in both shade and sun.
Lightly prune Lewis' mock orange in the early spring. Lewis' mock orange should be lightly pruned of dead branches to keep its shape and promote new growth. Dead branches will accumulate at the bottom of the bush, and can be removed gently with your gloved hands. If these branches do not come off easily, leave them in place on the bush.
Clear all dead growth from the ground area around the Lewis' mock orange every year. This will allow for better soil absorption around the plant.
Prune all old branches every three years to make room for younger branches. Using pruning shears, snip away 1/4 of the older, more mature branches to expose newer branches to the sun. Take care not to trim away any new branches, which will appear shinier and greener.
Trim carefully to keep the desired shape of the Lewis' mock orange. Depending on where the plant resides in the garden, you may want to trim away excess branches every year to make room for other plants.
Clear away all clippings and discard them, or chop them up to use as mulch in your garden.