Protecting your garden and Determining Cold Damage
When the weather is predicted to get very cold in late winter early spring after lengthy periods of warm weather, many things have begun to bloom or have flushed out new tender leaves. Here’s how you can protect your garden from frost.
Cover Tender Plants or Plants Leafing Out
Place frost cloth on after sunset tonight before the frost to help trap in the warmth. It’s important that you remove the frost cloth first thing in the morning. The sun can heat the plant underneath the cloth significantly quite quickly. If the frost cloth is not removed and the sun comes out the cloth will trap in heat and the heat will cause more damage to the plant than if you hadn’t covered it.
Some plants to cover include:
Trees & Shrubs with New Growth
- Japanese Maples
- Flowering Trees (if they are small enough)
- Tender Annuals
- Water, water, water: You should water containers before a hard freeze and after the freeze. The added moisture will allow the plants to tolerate the cold and bounce back to life.
- Don’t worry if your plants are droopy tomorrow after a deep freeze. Give them time and they will usually spring back to life
- Mulching your garden will help it regulate temperature and keep the plant moist which is important in protecting the plant.
- Your garden should have a good 1-2 inch layer of mulch
Determining Cold Damage
After a cold snap, you might wonder about the damage that you see to plants in your garden.
Some of the damage was immediately apparent. The fleshy stems of the aloe in the photo to the left, showed severe damage within the first 24 hours. All turgidity in their stems was lost.
While some damage won't be apparent or can't be fully assessed for weeks or even months.
Our first instinct might be to get out in the garden and prune damaged plants or pull them out to replace them. However, the best thing to do is wait. Give plants a chance to bounce back.
Many plants will recover quickly or show very little if any damage.This Euphorbia was covered in ice, but it wasn't damaged at all and is now blooming.
The Nandina below survived the freezing snow, but has some damage. The tips of the foliage have turned tan and are dry and brittle. In this case a simple pruning of the damaged foliage will make the Nandina look much better and it will regrow and fill out again quickly.
Some plants that look completely dead now will recover in spring once they start to actively grow again. They may have damaged stems and leaves, but their root system is still alive. You can scratch the stem of a smaller plant - or use a knife to make a thin knick a larger branch. If you see green, your plant is still alive and should come back out.
Once the weather warms up in spring and plants begin to grow, we will start to be able to fully evaluate their damage. We will be able to identify branches and stems of the plant that have no new growth. Then, at this point it will be time to prune back the dead portion of the plant to just above where new growth appears.
It is important to note that not all plants leaf out in spring at the same time. By mid April most plants should have some new growth. If there are no signs of new growth at this time, remove and replace the plant.
You might also want to replace damaged plants that are slow growers. They can be an eye sore for months and even years while they recover.The Pittosporum shown below is a slow growing shrub that suffered severe damage. Pruning back all of the dead branches will be a dramatic cut back. With its recovery being slower,you might decide to replace it altogether.
Some plants that do start growing again will grow in unpleasing shapes. They will need to be pruned again as it grows back in to encourage more consistent and uniform growth.
Also, wait to fertilize damaged plants until after they begin to grow again. During spring and summer make sure that they receive adequate water.
The key to assessing cold damage in your landscape is patience. Give the plants a chance to recover. As we begin spring, it’s time to start watching for new growth, and evaluate the damage. Many plants will recover. Replace plants that show no signs of growth or plants in prime locations. While, you might be fine waiting for a Loropetalum to recover in your back border, you might want to replace one planted by your front door.
Have more questions or concerns about your plants? Bring a photo or sample of your plant in to your local Pike Nurseries. We're here to answer your gardening questions.