Unfortunately, the inevitable has happened. Summer is winding down. Cooler days and longer nights are fast approaching.
Cooler temperatures are perfect for working in the garden. Perhaps it’s time to divide perennials that have become overgrown.
The ultimate reason to divide perennials is to prevent overcrowding. As a premium, gardeners will receive additional plants to relocate in their garden or give away.
For longevity, perennials must be kept fresh and young. Older specimens will only continue to grow around the perimeter of the plant and will eventually die out.
Another common ailment is that they will tend to deteriorate in the centre as they grow older. It is best to remove any dead parts.
Most, but not all, perennials benefit from division after they have grown for a number of years. They can be easily rejuvenated every three or four years. They are healthiest and most productive when they have room to spread.
Divided perennials can be relocated or placed in a container for future planting.
There is still plenty of time for perennials to re-establish themselves by growing new roots and getting ready for a cold winter ahead.
Only divide plants that look strong and healthy. If up rooted, weaker specimens will not survive the winter.
During the year, gardeners should keep an eye on plants that are growing “wildly”. Plant divisions can occur any time during the growing cycle. Once the growing season is over, the division should wait until spring.
Be on the lookout for warning signals. When the middle of the plant has smaller leaves, fewer flowers, or weaker stalks that flop over, it’s time to divide. A great example is the perennial sedum. It is notorious for the center of the plant flopping over when it becomes overcrowded. It has grown too many stocks that will push adjacent stocks to the ground or onto neighbouring plants.
To remedy this with minimal damage, dig a trench around the drip line. This will form a clump that can be visually divided. Transplants then can be easily pried upwards.
With a sharp, clean spade begin slicing deeply into the desired number of new plants. Discard any dead material. It is always best to sever roots with as much of the surrounding soil as possible. The most successful transplanting can be achieved by replanting to the new location as soon as possible. Adding compost will ensure a good start. Remember to keep all planted transplants moist until new growth is visible. When transplanting large roots from older plants, it is best to cut them at an angle down and under the clump. Do this from many points until the roots can be easily severed. Cutting plants back may make the task easier. Daylilies, peonies, ornamental grasses and hostas can be difficult to separate into smaller pieces. They are best removed by using two garden forks back to back, to pry the roots loose. Also, using a large knife or splitting with a spade may be useful.
Choose a time of the day when the sun or wind is not the strongest. Both will cause plant wilt after transplanting.
Moist conditions are essential for holding plant divisions until they are replaced back into the ground. Covering them with dampened Newspaper and placing in full shade will prevent severe moisture loss. To hold for a short time longer, sprinkle with water, not to dislodge soil around the roots, but to keep the Newspaper dampened. Plants that have become somewhat dried out can be soaked in a bucket of water for about one hour before replanting. Plants can be kept for a longer period if they are potted up. Always keep them in the shade or in conditions similar to a garden centre. Because of the recent move from the garden, they are under stress.
During extensive heat and wind periods, plants require numerous waterings to prevent damage from drying out. Extensive damage is usually irreversible.
Ron Stevenson is a member of the Fergus Horticultural Society
