This is the time of the year to move shrubs and trees that are growing in the wrong place. Every gardener, whether novice or experienced, has plants growing in the wrong position for a number of reasons, they may be a clash of colour, plants may have grown too large for their present position or a plant may not be growing well. It is easy to make a mistake when planting trees and shrubs, to discover within a few years that they have outgrown their allotted space. Once the error becomes apparent the plant should be moved before it gets too big. Moving plants a few years old is easy and is always successful. Young plants are quite easy to lift and will re-establish themselves successfully. Some plants like camellia, cornus, hydrangea and rhododendron can be dug up and moved even after ten years. Other plants like broom, ceanothus and eucalyptus will not move successfully once they are a few years old.
Deciduous trees and shrubs are best moved in winter or early spring. Evergreens should be left for another month or two when growth has started. Rhododendrons are evergreens that are easily moved at any age or size because they have a small root system of very fine roots.
Try to lift established plants with as large a root-ball as possible. Prepare the soil in the new planting hole well, digging in plenty of compost or well rotted manure. Replant the tree or shrub at the same depth in the soil as it was taken from. If planted too deeply the roots can die. Firm the soil around the transplanted tree or shrub, water it well and mulch with a layer of compost or bark to conserve moisture. It may be necessary to prune out a few shoots on large transplanted shrubs as the damaged root system may not be able to support all the new foliage on the plant.
To move old, large trees and shrubs successfully prepare the plant for the move the previous year. Dig a circle around the plant, cutting the old roots, this encourages new fibrous roots to form on the plant. When the plant is moved the following year it will have young roots to get the plant off to a good start.
Newly transplanted trees and shrubs will need staking to hold the plant in position until new roots enter the surrounding soil. Wind rocking of a newly transplanted tree or shrub will prevent new roots establishing themselves into the soil. The plant will need watering for two years or more. Give the plant an occasional heavy watering rather than small amounts of water daily.
Dividing Herbaceous Plants
Many herbaceous plants deteriorate after three or four years, their flowers become smaller and the clumps less vigorous. It is possible to encourage them to produce good blooms for a number of years by digging them up and dividing the clumps.
This is best done from autumn to spring when the plant is dormant. Using a fork, dig around the clump and lift it out of the ground. Pull the clump apart by hand or using a pair of garden forks. Separate out the sections with healthy roots from the outside of the clump. Cut away any that are dead or damaged.
The centre of the clump normally has many dead roots and this section can be discarded. Mature clumps can have a thick mat of roots, which can be difficult to divide. Replant the divided pieces in soil that has been enriched with compost and water well.
Plants that grow from rhizomes, such as irises, monarda, physalis, polygonatum and cannas are best divided in early spring when the new growth buds are starting to emerge. Cut the young rhizomes from the outside of the clump, making sure each rhizome has a few growth buds and healthy roots.
If the plant has leaves cut them back to about 6 inches, this will reduce rocking by the wind. Replant in well-prepared soil. Plant iris rhizomes so that the top of the rhizome is just exposed. Most herbaceous plants need to be divided every three years to produce quality flowers.