Resist the urge to prune

PATIENCE: Frost damage on a Diospyros whyteana hedge - the box hedge behind it wasn’t bothered at all. Many gardeners want to prune damaged plants as soon as possible, but Deb Delahunty says they should wait.
PATIENCE: Frost damage on a Diospyros whyteana hedge - the box hedge behind it wasn’t bothered at all. Many gardeners want to prune damaged plants as soon as possible, but Deb Delahunty says they should wait.

After a run of severe frosts, you may find plants in your garden that look burnt or have turned to mush – always a distressing sight. 

Light frosts don’t usually cause serious problems unless the plant is very tender. Severe frosts freeze the water that’s in the plant cells and this causes major issues. 

As water freezes, it expands – and if this water is inside a plant cell then the cell can rupture and cause damage to the plant.

The fastidious gardener is keen to prune and clean up the damaged plants as quickly as possible. My advice is to wait. 

We all know that pruning encourages and stimulates new growth, so cutting a frost damaged plant can cause the plant to produce new shoots, soft young shoots that will perish in the next frost. The frost-damaged growth is also serving a purpose – it’s protecting the undamaged tissue further down the stem. Pruning now will expose this tissue, this part of the plant will be the next to suffer if you get another frost. 

Only prune when there’s no chance of another frost. Wait until spring and then prune the dead stems out completely and prune live stems back to undamaged areas. A dose of liquid fertiliser is recommended to help the plants recover. 

Other frost damage to look for is cracking in young trees. These cracks in the trunks are the result of sudden drops in temperature during the night followed by a nice winter’s day. Unsightly as they are, these cracks will more often than not heal up beautifully with no intervention.

Of course, plant injuries caused by frost can be prevented, firstly choose plants that are suitable for your location, planting frost sensitive plants in our region is asking for trouble. Plants can be covered with burlap sacks or purchase frost mat from local suppliers, always remember to remove the covers during the day. Don’t use plastic sheeting because this doesn’t do a good job and your plants will still get burnt by the frost. Frost-sensitive potted plants should be put in a sheltered position.

Some people will go to extreme lengths during the winter – building cages around plants that are then filled with straw (this will act like insulation) is one of the extreme methods. It may do the job, but it’s a big price to pay to grow one frost-sensitive plant in your garden.

A bit of preparation prior to winter can stop parts of your garden turning to mush. Remember not to rush in and prune frost damage – put those secateurs away for a few months.

Diary

Kitchen gardening course at Wodonga TAFE over three half-days on October 9, 16 and 23. Runs from 9.30am-12.30pm. Cost: $250. For more information, phone 1300 698 233.