When (which months) can you plant bare root hedging?
Traditionally the season for planting bare root whips is November to March but in the last decade or so, that timeframe has been extended until April (and depending on the weather conditions for planting) sometimes even later into May due to the fact that stock is stored by growers like ourselves in cold stores designed to replicate the winter environment, and therefore the plants remains dormant even when, in nature, they would be budding and coming into leaf.
What considerations are there for the time of year to plant bare root whips?
- Do not plant when the soil is frozen or waterlogged, when there is a heavy frost forecast or when there are strong, cold winds which can dry out the plant roots whilst you have them out in the open air ready for planting. You can minimise the risk of wind damage by leaving all the plants in a bag and only taking out one at a time when you are ready to plant it immediately. The reason why you should not plant out on a frosty day is that the plant roots have a high moisture level and if that moisture freezes it causes irrepairable damage to the roots
- Do not plant (or be careful how you plant) in strong sunshine. Whilst sunshine makes the job more pleasant, a bag of plants left lying in the sunshine will soon overheat and the roots dry out so keep them in a shady spot and only take one out at a time
- If you plant in the dead of winter (November to mid-February) you are likely to benefit from plenty of rainfall after planting which will help the plants get established before their spring growth spurt. Whereas, if you plant in early spring (mid-Feb until April) you risk a dry, relatively mild spell just when plants really need to have plenty of water. Having said that, planting in early spring is often a much more pleasurable experience – there’s nothing nicer than getting out into the early spring sunshine to take on a big planting job! We used to be able to rely on “April showers” but with drier warmer springs in recent years, it’s worth checking the weather forecast before you plant to ensure there’s going to be some rain coming along soon after planting. Getting water to plant roots is really the most essential aspect of planting. In a domestic garden setting, “watering in” each plant immediately after planting is best practise but out in the landscape that’s not viable so you can help the plants by ensuring that the firming in is done well and then that there is some rain coming along soon – this will bring small soil particles into contact with all the fine feeding roots of each plant which is a critical success factor and often the biggest cause of bare root failures
- If you are planting late in the season (late March, through April, even into May) it is reasonable to ask your supplier two things – how many days out of cold storage will they be (we’ll explain more about that below) and have they come from a British or a Dutch grower? The reason for asking whether they come from Holland is that you know that they’ve come out of a cold store in Holland on one day, onto a pallet, then onto a lorry, across Holland to the port, then onto the ferry for an overnight journey to the port in the UK, then out for delivery to retailers the next day and then retailers store them ready for resale. That can sometimes add up to quite a lot of time that plants are out of cold store and whilst not disastrous in itself (and we know many retailers who do a really good job of storing their bare roots), if it is combined with a warm spring, then plants can start breaking bud whilst they’re still in storage and then when you plant them, you set them back a bit and some might fail. If you are buying stock that has been grown in Britain, you know that the length of time out of cold storage is minimised but feel free to ask your retailer about the grower’s cold storage arrangements – good retailers will know these details about their supplier
About cold storage of bare root whips
Cold storage units are farm buildings that are heavily insulated and have refridgeration and humidity units built into them. Doors are kept closed to keep the cold air inside and the light level is kept low enough so that we can see what we’re doing inside the cold store but gloomy enough to mimic winter to the plants. The refridgeration units are set to keep the air temperature at 1C – 3C (just above freezing point) and humidity units keep the air moist and therefore the plant roots are kept sufficiently moist. We always water plants well before they go into cold storage. Plants are stored (already graded by height and into bundles of 25 so that they are ready for despatch) in wooden crates with ventilation slats so that the cold, moist air can reach right into the middle of the stack of plants. All of this replicates “winter” to the plants and so they stay in their winter-dormant state for as long as the cold storage unit is in use. The cost of electricity is minimised by the high level of insulation but is still significant, but it does mean that the traditional planting season can be extended into April and sometimes longer with plants being kept in the best possible condition. Cold storage also gives us (and other growers) much needed flexibility in that we can lift (or harvest) plants when the weather is most suitable even if we do not have immediate customers for all of those plants – cold storage enables us to hold those plants in peak condition until they are needed by our clients.
Not every bare root grower in the UK has cold storage (some heel their plants in to light soil/sand outdoors instead), so always feel free to ask. It is particularly important to plant out quickly those plants that have been in cold storage because the natural light levels and warmth of spring will quickly bring them into bud/leaf and that will put a strain on the roots if they are not already planted out.
Which bare root plants are suitable for cold storage?
Basically any of the deciduous species are suitable for cold storage and evergreen species, which never go fully into winter dormancy, are not suitable.
Advice on planting bare root plants
We have several advice pages on our website which cover how to store bare root plants, how to plant bare roots, and planting density for bare root hedging and tree saplings.