Cordyline Calamity

By all accounts garden waste recycling centres are full of dead cordylines. We didn’t know it at the time, but a few weeks ago when the cold snap was upon us, anyone who didn’t put some form of protection like an old sack around their prized specimens and tied them up, risked losing them to the frost. Ours was about fifteen years old and you would think it was hardy enough to withstand the winter. We were wrong. The devastating damage only became apparent about a month after the worst of the weather had gone. The usually upright growth of the long leaves growing from the top of the eight foot trunk started to hang down and look sorry for themselves. Then, when the wind blew I found myself outside picking up the long tapering leaves all over the driveway. It was obvious something was wrong.
After filling up the compost area with the fallen leaves I checked the centre of the growing crowns. They were not too bad. The problem was that the cold weather froze the soft spongy stems that held the leaves in place. It had turned to mush. It doesn’t pay to panic when a plant such as this is damaged as they can throw out offshoots from the base, but on closer inspection I noticed that the base of the trunk was covered in a white mould and seeping badly. The trunk was rotting too. Fed up of picking the leaves up and being realistic about the inevitability of the plant dying completely I got out the bow saw. Within a few moment the cordyline was just a long seven foot trunk with two bare branches that looked like two fingers pointing up to the sky. The poor plant put up no resistance.
I have asked a few people around the country about how they got on with their plants and the stories are the same. Gardeners in Cork, Clare, Leitrim and Monaghan are all chopping away. Cordyline trunks are very soft, wet and fibrous and try as you might, they will not burn in the fire. That’s why people are taking them to the recycling centres; it’s probably their survival method for life in hot climates. If you have the room in your garden I would recommend that they are laid down and left as hideaways for frogs and newts, they will love the dampness.

So how can we tell what other plants have been affected by the cold?

Frost hardy plants can still suffer if they have soft growing tips early in the season. Frost damaged plants are easy to spot, their growth becomes limp, blackened and distorted and there is some die back on the stems. If they are shrub new growth should sprout from lower down the stem and you won’t notice the difference come late spring. With semi tender evergreens, some of the younger leaves could either turn brown or take on a translucent appearance. Frost problems are often made worse where plants face the morning sun, as this causes them to defrost quickly, rupturing their cell walls. Our escallonia turned brown again this year but is starting to pick up well; these are tough evergreens but could suffer in prolonged cold snaps when soil becomes frozen. Roots can’t take up water and plants die from lack of moisture. Periods of cold, frosty weather during April and May can also kill blossom and damage fruit.
Minimising damage

It’s inevitable that we will get frost damage to our plants. There are a few things we can do to minimise the damage though. Firstly choose plants that are really adapted to the area and hardy. Our local garden centres will advise you on what to get. Let them know the gardens vulnerabilities, prevailing winds, shade, frost pockets and any other information that might be of note.

Here are a few more ideas;

• If you have a particularly cold site, steer clear of golden or variegated plant varieties that are often more tender. They grow more slowly too, which might not suit everyone.
• Avoid high-nitrogen fertilisers and don’t feed too late in the growing season as they encourage plants to make lots of sappy leafy growth that is particularly susceptible to damage, especially early and late in the year.
• Make sure tender specimens are planted in a sheltered spot, under large trees and shrubs or against walls, give them some heat and protection during the winter if possible by potting them up and putting them in the greenhouse.
• Once the temperature has fallen below freezing, a strong wind can make a frost more damaging. Cold winds remove moisture from evergreen foliage more quickly than it can be replenished by the roots; this can cause leaf browning particularly at the tips and margins.
• Try not to put plants with tender flower buds or shoots are not planted in east-facing sites.
• Leave the old growth of tender plants unpruned over the winter months. This helps to protect the central crown of the plant and take the brunt of any frost damage. If plants are cut back hard in autumn new growth could be damaged by frost. The architectural stems look fabulous in winter and give protection to insects too.
• Cold air and frost always descends to the lowest points of a garden. Check out the coldest parts of your garden and see where the frost is worst, and avoid planting tender plants in there.
• Tender plants survive the winter better when they are planted in a sheltered sunny position. The new wood of the plant is ripened by the sun accumulating more carbohydrates during the growing season, making it more frost resistant.
• Mulch the root area of evergreens, conifers, tender shrubs and tender perennials with a thick layer of organic matter to prevent the ground becoming frozen.

Don’t give up

Do not automatically give up on a plant that has been frost damaged. I pondered over the cordyline for a while and it was only when I saw the fungus had sat in that I realised it couldn’t be saved. A lot of plants can be surprisingly resilient though and may well rejuvenate from dormant buds at or below soil level. This takes time so recovery may not be seen until later. If you can leave the plants until mid summer to see if anything stirs. If there are still no signs by then it’s time to take them out and find something a bit hardier. I’m sure we haven’t seen the last of these cold winters just yet.

UPDATE
New growth from the base of the stump...June 2011