Mistletoe Care Guide: How to Grow Mistletoe

Mistletoe Propagation

The best time to sow mistletoe is February or March. Ideally, you should harvest fresh berries around this time. If you have an existing mistletoe plant, you can harvest berries from this, otherwise, ask someone who has a plant if you can harvest some from them. If you do not know anyone who has mistletoe you can buy the plants online.

Choosing berries for propagation

Make sure the plants you buy are freshly harvested. The berries should be plump, not dry and withered and the foliage should look fresh and green. The berries should also be white. Green berries are not mature. It is not necessary for the mistletoe to have been growing in the same species tree as you plant to grow yours. The mistletoe will grow in any suitable host tree.

It is not usually worth trying to germinate seeds from mistletoe sprigs bought as Christmas decorations as these are often harvested before they are mature and dry out in the heated indoor atmosphere over Christmas.

You can keep the mistletoe for up to three weeks in a cool place before using. Do not keep them in the dark, or in a fridge. The seeds will die without light!

Propagating your mistletoe

To propagate your mistletoe, you will need to choose suitable branches that are quite young and around 5-10 cm in diameter. Choose branches that are fairly high as these will get more light.

If the plants have been stored for a while put them in some water for several hours so that they rehydrate. Discard any berries that are already split or crushed.

Take your fresh or rehydrated berries and squeeze out the seeds. They will come out in a jelly-like substance called viscin. You can remove most of this but leave just enough that the seeds have something to stick with.

Some sources advise cutting a flap in the bark under which to insert the seeds. However, this is usually unnecessary and inadvisable as it can damage the tree and allow diseases, pests and fungi to get in. Anyway, mistletoe seeds need healthy host bark and plenty of light to grow.

Mistletoe seeds are very sticky and will easily attach to the bark of the host tree. You may like to put some netting over the seeds to protect them from birds.

You should plant about twenty seeds, spread across four branches. Not all the seeds will germinate, and some may be lost to birds or insects. Planting more seeds also increases the likelihood of propagating both male and female plants, which is necessary if the plants are to produce berries.

Label the branches you have put your seeds on as the seedlings can be difficult to find.

Mistletoe germination and growth

When your seed germinates it will produce a hypocotyl which will bend towards the bark of the host tree. Once it has made contact with the bark it will flatten and attach itself to the bark like a sucker. The seedling then penetrates the host tree and create a haustorium. The haustorium enables the plant to penetrate the tissue of the tree and absorb nutrients from it. You will see a swelling on the tree branch at the place the mistletoe has penetrated.

Mistletoe is initially slow growing. For the first two years, you may see barely any growth and may even think your mistletoe has disappeared as it becomes camouflaged with algae. If your seedling has died it will turn yellow and shrivel away.

After the first year, your seedlings may well still be very tiny. However, they should be greener and more upright by now. By the third year, you should see some proper leaves. After this, the plant will begin to grow more quickly, doubling its branches at least once a year. It may take five years for a plant on an apple tree to grow berries and even longer on some other host trees.

If your plant produces flowers but no berries it is a male plant. If this happens, insert some more seeds on other branches to increase the likelihood of producing a female plant to complement your male.

Mistletoe berries contain potential toxins, so they should be kept away from pets and children.

Pruning advice

In large trees, mistletoe can often be left to itself. However, in small trees, some management is required to make sure the mistletoe does not overwhelm its host.

It’s is best to prune your plant in winter when the host tree’s branches are bare, and the mistletoe can be easily seen.

In general, it is wise to cut back one-third of mistletoe growth on smaller trees each year. In addition, any heavily infested branches may need some of the plants removed. You can also rub off any new seedlings that are growing in places where they are not wanted.

Many people make the mistake of harvesting the female plants for decoration at Christmas time and leaving the male plants untouched. This can mean that over time they become too large. It is best to cut back the male and female plants equally.

Mistletoe will affect the vigour of your tree, so you want to ensure that some branches are left free of the plant. The tree branches that have mistletoe will have a swelling where the haustorium has grown. This can lead to the rest of the branch becoming distorted or dying off. This means that this branch will no longer be serving the tree. Obviously, if this happens to all the branches the tree will struggle to survive.

In addition, mistletoe can make your tree more susceptible to wind damage. In winter, your deciduous tree will shed its leaves and be less affected by winter storms. The mistletoe will create resistance and may lead to damage in winter weather. This is another reason for keeping the plants small, especially in smaller, younger trees.

Failure to maintain a good balance between mistletoe and the host tree will mean the death of both the tree and the mistletoe.