This page gives advice on growing mistletoe from seed and, for where there is long-established mistletoe, advice on how to manage mistletoe long-term. Quick links to both sections are:
Many people in Britain want to grow their own mistletoe – but often get conflicting advice on how to do it. There is almost a whole mythology about it, due to misunderstandings of what mistletoe needs and how it grows. Some of the usual myths (often repeated by gardening ‘experts’ in the media) are listed below. Some of these are completely counter-productive and will minimise, not maximise, your chance of success!
- “seeds have to pass through a bird to germinate” – false!
- “seeds need the fertilisation from bird droppings to germinate” – false!
- “seeds should be placed under a flap in the host bark” – false!
- “seeds should be covered in muslin/raffia/etc to hold them in place” – false!
- “seeds must be planted on the same host as their parent plant” – false!
- “the best location is in old fissured bark” – false!
Growing advice given below is for Viscum album and may not be suitable for other species of mistletoe.
Stages of germination
Germination can be divided into non-parasitic and parasitic phases. In the first the seed extends one or more green hypocotyls which bend towards the host bark, forming a disc-shaped holdfast when they reach the bark surface.
After this the parasitic phase begins as the seedling begins to penetrate the host tissue, connecting to the host cambial cells just below the bark and stimulating the growth of a connecting haustorium. This haustorium, which will appear as a swelling where the mistletoe is attached, is a mix of both host and mistletoe woody tissue.
No need for making cuts or covering seeds
Disregard any advice you’ve heard or read that suggests cutting flaps in, and hiding seeds under, host bark. This is completely counter-productive – mistletoe seeds need intact healthy host bark and need to be in light to grow. They are naturally sticky, and so simply glue themselves onto the bark surface. Smooth thin bark on side branches is most suitable, not thick bark on trunks.
Don’t store seeds for long, never in the dark, and make sure you have a lot of them.
Mistletoe seeds germinate best in February and March, not at Christmas. You can keep Christmas berries fresh by detaching them and leaving them in a shed window until mid-February – though this is not ideal. Even if you keep them for a short time don’t keep them in the dark (and never in the fridge) as the seeds – and the tiny seedlings later – are actively photosynthetic and need to be kept in the light, otherwise they will quickly die.
Germination is easy, if the seeds are placed as above – but many seedlings are eaten by invertebrates or fail to connect to the host, so you will need several to be sure of success.
Time it right and be patient
Germination success is highest when planting in February to March. After germination and bending round to the bark the seedlings develop very slowly. There will be no visible change for at least 12 months – progress during this period is all under the bark.
If host connection is successful it will be about four years before you get a significant plant. But it grows quite fast once it is well-established.
More information and supplies
More detailed instructions are available on this information sheet: Growing Mistletoe – dos and don’ts
You can order a grow-kit, delivered in February or March, with fresh berries, detailed instructions and labels from the English Mistletoe Shop here: English Mistletoe Shop
All vegetation needs management from time to time, and mistletoe is no exception. Indeed, as a parasitic plant, it has particular management needs as it directly affects its host and will need, eventually, to be kept in check.
Some mistletoe species around the world are considered forestry and tree pests, whilst others are relatively harmless. In Britain Viscum album is relatively benign but it will always significantly affect the branch it is on and will need management if allowed to colonise too many branches.
Don’t worry though – garden and conservation project plantings, especially in new locations, will not need significant management for many years! But it is best to consider regular management once plants are established.
Effects on the host tree
Mistletoe affects the host tree in several different ways. The most obvious is the way it takes over the branch it is growing on, with the host’s growth (cambial) cells fooled into developing wood and bark enclosing the developing mistletoe plant from germination onwards. The resulting distorted growth (the haustorium) can become quite large and often leads to any distal parts of the original branch becoming stunted.
The evergreen nature of mistletoe is another obvious impact – the mistletoe’s retention of leaves throughout the winter increases windage of the tree – which can be a problem in winter storms.
Another impact is less apparent and relates to water and gas exchange. Most mistletoes, Viscum album included, tend to preferentially absorb and transpire more water than the host. This can be a problem in summer and dry periods when the mistletoe’s excessive (and somewhat uncontrolled) transpiration can lead to the host reacting by closing its own stomata, further reducing water for the host. There are then knock-on effects for carbon assimilation, as the closed host stomata mean limit gas exchange and will reduce photosynthesis in host tissues.
These effects are usually only significant where there is excessive mistletoe.
Traditional management in orchards
Impacts of mistletoe on relatively small trees can be significant, especially on crop trees. So mistletoe has, traditionally, been managed in the English SW Midlands, where mistletoe and apple orchards are common.
Work usually takes place in winter when mistletoe is better assessed and is often combined with a ‘harvest’ for Christmas, using the mistletoe as an extra crop. This serves as sufficient management when carried our regularly – but many old orchards are now not managed much at all (see below).
Across the channel in northern France, mistletoe management was, at one time, a legal requirement in orchards. This obligation, for French farmers to cut mistletoe out from orchards, may have helped the cross-channel trade in Christmas mistletoe as the British eagerly bought the French ‘waste’!
The decline in traditional style orchards over the last few decades, in both Britain and France, has changed the dynamics of mistletoe management in apple orchards. Many surviving orchards in mistletoe areas are not managed at all, with excessive mistletoe often the norm. When there is ‘management’ it is often, in reality, a Christmas ‘harvest’ rather than genuine management. This can mean that only berried female mistletoe is cut, leaving male plants uncontrolled.
Similar neglect is sometimes seen in garden situations, where a few decades of mistletoe growth can smother a small apple tree, looking delightfully romantic for a few years, until premature death of both tree and mistletoe. Far better to manage the mistletoe and keep both tree and mistletoe indefinitely!
Management techniques – regular, proportional, and both sexes!
There is no standard technique for mistletoe management – and much depends on whether the task is regular annual work or irregular remedial work following decades of neglect. For regular management the first need is to decide your objective – decorative mistletoe in a garden, a larger quantity for heritage and/or nature conservation objectives, primarily female plants for a Christmas cash crop, or simply maximising host tree productivity (i.e. attempting total control where mistletoe is common).
Whatever the objective similar management principles apply:
- management will not be needed for new plants/colonies until many years after establishment
- male and female should be equally cut, even when harvesting for Christmas when the unberried male is valueless
- the winter shoot tips are spring flower buds, so if berries are wanted some of these must be retained
- a pre-planned proportion of growths can be cut back each season – a rotation system can be helpful
- mistletoe is difficult to kill – it will re-sprout if cut back to host bark. This can be a useful management tool as it will set back plants without killing them
- total control may only be possible by cutting out whole branches
Information Sheet on Management
There is an information sheet on mistletoe management issues here: Mistletoe management – the need for control