The yellow butterfly magnolia (Magnolia acuminata 'Butterflies') bears creamy yellow blossoms and displays yellow autumn foliage. This magnolia cultivar reaches 18 to 20 feet in height and has a spread of 15 to 18 feet. Magnolia trees do not respond well to pruning and may develop infection or disease after a pruning. The University of Washington recommends pruning yellow butterfly magnolia only when it's necessary and removing no more growth than you must.
Inspect the branches of the yellow butterfly magnolia for signs of dead, diseased or damaged branches any time from summer to late autumn.
Mix a solution of 1 part bleach and 10 parts water in a bucket. Place all pruning tools in the bucket.
Cut off unhealthy limbs at their base. Prune back to a Y-intersection if the wood below that point is healthy. Remove wood with a 3/4-inch diameter or less with anvil pruners. Cut larger branches with lopping shears. Dip the tools into the bleach solution to disinfect them between each cutting. Discard the bleach solution when the pruning is finished.
Control the size of the yellow butterfly magnolia by removing select limbs. Cut these limbs off at their base or down to a crotch intersection.
Remove limbs that press against other limbs or cross other branches.