If during or at the end of winter the leaves of a bamboo (Bambusoideae) turn brown and/or the plant appears dead, many hobby gardeners think it has frozen. Contrary to popular belief, however, this is rarely the case because bamboo usually dries up. How to recognize whether it is frostbite or dehydration and what needs to be done to ensure that the plant survives can be found below.
Bamboo is brown
If individual leaves turn brown and fall off in autumn, this is usually a normal process, even though bamboo is an evergreen plant. This is therefore usually not related to a drought. If the temperatures have not yet fallen far below zero degrees Celsius, this cannot indicate frostbite. In the normal process, only a few leaves are affected at a time. The rest stays green and goes through the winter. In the spring the Bambusoideae will sprout again and fill any vacant spots.
damage picture
When it comes to damage, it is important to distinguish between frostbite and desiccation. These are easy to recognize based on the following characteristics:
Bamboo has dried up
- Leaves curl up first (to reduce evaporation)
- Leaf green gradually decreases in intensity
- leaves hanging
- Then turn brown and look dried up
- Basically, several/many leaves are affected
- In the final stage almost all leaves are brown
- The stalks become paler
- Dried roots: Plant loses elasticity, colour, increasingly withers and dies
Plant is frozen
- Leaves turn brown from the leaf tip towards the stem
- Brown tone is darker than dried leaves
- Dark brown discolouration often also on the petioles
- Leaves hang, usually do not fall off
- Usually only individual regions are affected
- Very susceptible to fungal diseases
- Very stunted new shoots in spring or die off
causes
desiccation
winter drought
As an evergreen plant, a Bambusoideae also needs moisture over the winter because it evaporates it again through its leaves. If the winter stays very dry for a long time, and there is no rain and/or snow, the hobby gardener is asked to cover the water requirements of these specimens by watering them. If it doesn't get water, it dries up.
dry frost
The cold is his lesser problem here, but the so-called dry frost is causing him problems. A layer of ice forms on the ground and the frost penetrates a few centimeters deep into the ground, where the roots are usually much better protected than in a bucket. But the dry frost compacts the surface of the earth. This means that no more moisture gets into the soil. Moisture evaporates, especially on sunny days, while no new moisture can be absorbed via the roots. The result: drying out.
root
Especially young bamboo plants with their still fine root system, but also roots that are only planted in autumn are not able to establish themselves and spread out in the first two to three winters so that they can absorb enough water. They are particularly prone to dehydration.
Fargesia murielae, umbrella bamboo, Muriel bamboo
frostbite
hardiness
Most varieties of this sweet grass are hardy. As a rule, frostbite is not found in the cold-resistant varieties, although there are a few exceptions. This is the case, for example, with non-hardy varieties that are only frost-resistant to just under zero degrees Celsius, and with "moderately hardy" varieties that are exposed to extreme minus temperatures below 15 degrees Celsius for a long time.
root
It should be noted here that the roots of a bamboo planted in autumn have by no means established themselves and also need two to three years at their location to develop their full winter hardiness. It should also be noted that potted plants are much more exposed to the cold than a Bambusoideae in the garden bed.
measures
desiccation
To cut
If the first signs of drying out appear in winter, cut off the bottom leaves and water the affected plants. If stalks have dried up, they should be cut off near the ground to make room for new shoots in spring. If the bamboo is brown due to drying out, no matter how badly, these measures will sprout it again in the forthcoming growing season.
pour
When watering dried bamboos, it is important that they lukewarm water be cast. If a layer of frost has settled over the surface of the earth, it must be thawed with lukewarm water so that the water reaches the soil and the roots.
tip: Never use hot water because the temperature difference is too high and it may damage the plant.
frostbite
To cut
Only in spring should you cut the affected plant. Pruning back in winter could increase freezing temperatures and the risk of frostbite and fungal infections. From April, nothing stands in the way of a radical pruning. If no new shoots have appeared by summer at the latest, it can be assumed that the plant has died. As a rule, this only happens very rarely.
Prevent
meet water needs
Regular watering in dry and/or icy winter times is essential to prevent the causes of drying out.
Cold protection for roots
Cold protection should not be delayed on moderately or non-hardy specimens, as well as on young specimens until they have frostbitten. Even before the onset of frost, a cold protection made of brushwood, straw, leaves or pine needles should be laid out over the root area. At extremely low temperatures and especially with plants that spend less than three years at their location, a fleece should also protect the plant.
tip: Tying the culms together in autumn for winter preparation allows less cold wind to blow through the bamboo and reduces evaporation, so there is less chance of dehydration and/or frostbite.
pot plants
Buckets should be placed on an insulating base such as wood or styrofoam. The bucket can be covered with foil or fleece so that the cold does not hit the roots with full force and the soil in the bucket freezes.
location
A sheltered location reduces the risk of frostbite and dehydration. Under no circumstances should potted plants be moved to warmer climates if they have already been exposed to winter temperatures. Bamboo rarely survives high temperature fluctuations.
planting time
Spring is the ideal time to plant bamboo. If the deadline is missed, YOU should plant no later than mid-September. After that, the period until the onset of frost is too short for the roots to be able to establish themselves reasonably well and grow deeper.
hardiness
In view of the fact that colder winters are expected, it makes sense to pay attention to an extraordinary winter hardiness when buying a bamboo. From "moderately hardy" the chances that the bamboos will not suffer from frostbite increase immensely.
