But as leaves start to lose their green colors in fall and winter, they can no longer do photosynthesis. If the temperatures are warm enough in winter, the stems start to photosynthesize. But in this case, the tree doesn’t take carbon dioxide from the air. Instead, it uses some carbon dioxide that it makes on its own.

If you live somewhere that never freezes, but your plants are still dying over the winter, they may be getting excessively wet during their dormancy. Look closely at your watering practices if your plants’ warm weather dormancy seems to be a chronic death knell.

Cutting down spent flowerheads and stalks at the end of the growing season is a ritual for some gardeners. In cold weather climates this is often done after the first hard frost, when flowering stops and plant parts blacken. In frost-free climates, it can be done in late fall when flower production slows or stops.

7 plants for your garden that can survive all types of weather

• Euphorbia Characias. Commonly known as the Mediterranean Spurge, this green plant can grow up to 1.2 metres in height.
• Hydrangea Arborecens ‘Annabelle’
• Rosa ‘Wedding Day’
• Iris Pseudacorus.
• Geranium Phaeum.
• Primula Vulgaris.
• Hemerocallis ‘Burning Daylight’

Bed sheets, drop cloths, blankets and plastic sheets make suitable covers for vulnerable plants. Use stakes to keep material, especially plastic, from touching foliage. Remove the coverings when temperatures rise the next day. For a short cold period, low plantings can be covered with mulch, such as straw or leaf mold.

While many people ask how much cold will kill a plant, the real question should be how much freezing will kill a plant. Light frost typically doesn’t cause major damage, with the exception of very tender plants, but a hard frost freezes water in plant cells, causing dehydration and damage to cell walls.

A light frost may cause minimal damage while a severe frost may kill plants. Young, vulnerable plants are much more susceptible to a light freeze, which occurs when temperatures are 29 to 32 degrees Fahrenheit, while mature plants may only suffer from short-term effects.

In gardening terms, a “light freeze” or “light frost” refers to temperatures that fall just a few degrees below freezing for a few hours. A “hard frost” or “killing frost” comes when the temperature drops further, below 28 degrees, for a longer time. It will kill the top growth of most perennials and root crops.

Check the water needs of plants after a freeze. Water that is still in the soil may be frozen and unavailable to the roots and plants can dry out. It is best to water in the afternoon or evening the day after a freeze so plants have had a chance to slowly raise their temperature.

Irrigation sprinklers can be used to protect plants from freezing when the expected lows are just below freezing. Irrigation will result in severe damage when the low is below the temperature you can protect to. As long as you keep the ice wet, the ice temperature will stay at 32 degrees F.

What to do with your plants after the freeze.

1. Wait! Don’t hastily pull out freeze damaged plants.
2. Wait!
3. Wait a few days after the freeze to assess plants.
4. Wait to fertilize, but offer normal amounts of water (don’t go overboard).
5. Wait and decide if you even want the freeze damaged plant.

Treating Cold-Damaged Plants

1. Water. After a freeze, check the soil around your plants.
2. Fertilizer. While you may be tempted to add a little fertilizer to your plants to help speed their recovery hold off.
3. Pruning. Don’t prune cold-damaged plants right away.
4. Lawn.

The damage occurs when ice crystals form within plant tissue, damaging their cells. Leaves and tender new growth are usually affected first. It is tempting to remove frost-damaged plant growth immediately, but dead material should be left on the plant until the full extent of the damage is apparent in the spring.

Spraying Your Plants is a Better Option When water freezes, it issues heat. So, if your plants have a small layer of water on the areas that freeze, it actually helps keep them warmer. Additionally, the sheet of ice (which is a good insulator) will then help keep the plant warmer through the cold spell.

First, the good news. A sudden brief late freeze is not likely to kill or cause long-term damage to your shrubs and trees, though the early leaves and blossoms may suffer some real damage. Once the plant has fully leafed out, the freeze damage may not even be visible.

Use a white commercial tree wrap or plastic tree guards. Do not use brown paper tree wrap or black colored tree guards as they will absorb heat from the sun. Wrap newly planted trees for at least two winters and thin-barked species up to five winters or more.

Most saplings will be fine in temperatures 35° or higher. Young trees are at risk of damage from the cold when temperatures hit the lower thirties. To keep your new trees out of harm’s way, cover your trees if temperatures consistently fall below 35° degrees.

Some hydrangeas can die because of freezing temperatures and cold winter winds that cause the plant to dry out. Cold weather can pull moisture from stems and leaves, causing dehydration. A late frost in early spring can damage new growth on hydrangeas that bloom on new wood.

Fortunately, even if a large proportion of the new growth has been affected, you can still usually help hydrangea recover from frost damage. You can work out how much of the new growth has been killed by scraping your fingernail across damaged stems. Scrape back the bark with a fingernail at various locations.

These mophead or lacecap hydrangeas traditionally bloom only on old wood. If cut back too hard or to the ground in late winter, there will be no flowers. These can be cut (or frozen) to the ground and still bloom through much of the summer. Prune them lightly early in the season to encourage new growth and flowers.

The primary reasons hydrangeas don’t bloom are incorrect pruning, bud damage due to winter and/or early spring weather, location and too much fertilizer. Hydrangea varieties can be of the type that blooms on old wood, new wood or both. Nikko’s produce blooms in the fall for next year.

Hydrangeas that bloom on old wood do not need pruning and are better off for it. If you leave them alone, they’ll bloom more profusely the next season. Just remember new growth may come, but that new growth will be without blooms next season.

Most new growth hydrangeas put on buds in early summer to bloom in the following spring, summer and early fall seasons. In hot climates, hydrangeas may stop blooming in the heat of summer, but will rebloom in the fall.

Old wood is quite simply, last year’s wood. Hydrangeas that bloom on old wood set their flower buds in late summer on stalks that have been on the plant since the previous year. Hydrangeas that bloom on old wood include the mophead, bigleaf (macrophylla), lacecap and oakleaf varieties.