The last two weeks of September and every week in October are the best times of the year for planting and transplanting into our gardens. Our fall temperatures are mild and our winter doesn’t begin until the first frost, usually in mid-November.
Almost any perennial plant or tree can be transplanted in the next six weeks with little anxiety over heat stress. However, care must be taken when moving plants and trees to minimize transplant stress. When transplanting, first irrigate the soil deeply under the leaf canopy to moisten the root ball. Then, use a spading fork, not a shovel which can sever roots, to rock the plant and the root ball out of the hole. Insert the tines of the spading fork at the perimeter of the leaf canopy in several spots and gently lift the rootball. Some longer roots may need to be trimmed but try to keep as many roots intact as possible.
The new planting hole should be prepared ahead of moving plants or trees. Dig a hole twice as wide as the root ball but no deeper (most of a plant or tree’s roots lie within the top 12 inches of soil), then fill the hole with water and allow it to drain. Amend heavy clay soils with gypsum or gypsite and compost; amend sandy soils with compost or humus before placing the plant in its new spot and refilling the hole with dirt. A cupful of sulfur granules mixed into the amended soil will help lower our high soil and water pH levels, an important step when planting shade plants including azaleas and camellias and roses which do best in more acidic soil with lower pH conditions.
Place the plant into the hole, gently arranging the roots to form a circle if possible. Fill the hole halfway with dirt, then fill the hole with water again. Let the water drain, finish filling the hole with dirt and firm the soil around the trunk.
The soil in the new hole will subside over a period of several weeks. Keep the bottom of the trunk an inch or two above soil level at planting time so that as the soil settles the trunk will be just below soil level.
Wait a couple of weeks to fertilize, then sprinkle a low number granular fertilizer at half the recommended rate , say a 4-6-2 formulation, around the plant or tree. Fruit and nut trees need fertilizing in fall with a higher nitrogen food. Ammonium sulfate which has a 21-0-0 formulation indicating a 21 percent level of nitrogen is a good and cheap source of nitrogen for fruit and nut trees as well as lawns.
What we don’t have in September and October is significant rainfall. Most of our rain arrives in early spring. As deciduous trees and large landscape plants go into dormancy in fall, they’ll need deep, slow irrigation over a period of several hours every couple of weeks. Increase the number of drip emitters in the plants’ new spot and provide supplemental irrigation with bubbler attachments on a hose or soaker hoses.
Send Elinor Teague plant questions at firstname.lastname@example.org or email@example.com (“plants” in the subject line).