Tips for Overwintering Citrus Trees
Watch our top 10 tips for looking after citrus and learn how to get the most from these rewarding plants.
As the weather and day length changes, so does the care that your citrus trees need. Because sometimes people can be caught out by this, we've put together our top 5 tips to remember for this season.
As the temperature drops water evaporates more slowly but also because your citrus tree is no longer putting on new growth, the amount of water your tree will need will be considerably less in the winter months.
As always water heavily from the top and let the excess water drain away. Don't let your citrus tree stand in water and don't water again until the top of the soil starts to feel dry to the touch.
In our Nursery we have gone from daily watering in summer, to twice weekly watering in autumn to once every 7-10 days at the moment. How quickly the top of the soil dries out for you will depend on the position and temperature you are keeping it in and even the size of the plant compared to its pot.
We all love sunshine, citrus more than most. Remember most citrus prefer to be above at least 5C in the winter. That means the coolest but very lightest place you can find indoors.
Citrus trees fall into 3 main categories for hardiness:-
Non-hardy Calamondins, Sweet Oranges, Kumquats, Tahiti Limes, Grapefruits and Mandarins should be kept above 5C and it's best to move them inside before the night time temperature drops much below this and wait until late Spring before they go back outside. Choose the sunniest place in the house away from draughts and radiators.
Nearly hardy Lemon trees, Chinottos and Kaffir limes will be fine in temperatures right down to zero and will even tolerate -1C or -2C for short periods. This winter has been quite mild so far so we know many people have chosen to keep their trees outside. In wet weather do just make sure that your tree is not sitting in a puddle of water and that it protected from the worst downpours. Keep an eye out for any hard frosts and remember it’s not the leaves you need to worry about but the rootball – this must not freeze!
You can wrap the pot with hessian or fleece to extend the season outdoors and/or bring it close to the wall of your house to give your tree a bit of extra protection. When you think it is going to be too cold overnight it's best to move your tree to a new position for the coming months rather than try and move it in and out and every day.
Hardy Yuzus and Finger Limes can withstand temperatures down to -15C. It's still best to keep these in a pot as they will suffer if they become too waterlogged but these hardy varieties are grown on Poncirus trifoliate stock and should withstand all that a British winter can throw at them.
In the middle of winter our dark, rainy days can lead to some leaf drop even if you are doing everything right. Kaffir Limes, Kumquats and some Lime trees seem most susceptible to this and once the days start to get longer they will pick up and put on new growth. In the meantime try to ensure they are getting as much direct sunlight on their leaves as possible.
Indoors you don't need a conservatory but just a nice big window to place your tree or trees beside. Try to choose a place that is free from draughts and away from any radiators (especially under floor heating) and where the temperature is reasonably constant. Most citrus will overwinter very well even in quite warm houses but if your tree does start to suffer mid winter, hang in there - spring is just around the corner.
3. Winter Feed
Citrus benefit from a balanced Summer and Winter Citrus Feed. This is in addition to the free plant tonic we include when your tree is delivered.
The Summer Feed has more Nitrogen for leaf growth and the Winter Feed has proportionately more Phosphorous and Potassium to help develop fruits. At this time of year you should be using a Winter Feed every other watering to keep your tree at its best.
You should be able to buy citrus feed from a good garden centre or of course you can buy the citrus feed we use for £6.95 and have it delivered free of charge. Buy winter feed
4. Watch for Leaf Drop
Citrus trees are not deciduous. One or two leaves is not too much of a concern but more than this and it’s a sign that your tree is unhappy. This is almost always to do with too little or too much water – not sure which? And it can be tricky – Give us a call on local call rate 0845 226 8026 or on 01825 721162 and we’ll do our best to advise you.
Other things that can cause leaf drop are sudden or dramatic changes in temperature, under floor heating or being too near to a radiator or being in too draughty a position - but again if you're not sure - do get in touch.
January and February are the toughest months of the year for citrus trees when overcast skies and short days mean they are surviving on minimal light for weeks on end. Some varieties are tougher than others but we find even in our greenhouses with maximum light, some of the limes particularly, will develop a bit of leaf drop at this time of year.
Once the days get longer, this will settle down and they will soon replace these leaves with fresh foliage in the spring. If your tree has lost more than a handful of leaves do give us a call though and we'll just check through that there is nothing else that you can do.
5. Treat early for Pests
Outdoors birds and other insects plus the cooler temperatures will keep most pests at bay. However, indoors over winter, the warm conditions can become breeding grounds for pests.
Scale, mealy bug, red spider mite, aphids and caterpillars all do like citrus trees but the trick is to catch them early. Round brown circles, white sticky fluff, webbing, holes in the leaves or stickiness are all signs of pest attack and should be treated as soon as possible. A soapy washing up liquid solution is normally good enough if the infestation hasn't got too advanced. Spray on to the leaves morning or evening a few times a week until it's cleared.
Not sure what you've got? Send us a picture by email or give us a call and we'll be more than happy to help you identify any problems.
And finally.... don't forget to enjoy the fruits of your labour!
Although citrus don't always follow a strict fruiting season in the UK, they do usually fruit in the winter months. Lemon Meyers, Limes, Grapefruits, Kumquats and Clementines will naturally drop when they are ripe, but Lemon4seasons, Calamondins and Chinottos will need to be picked off the tree when they are fully coloured.
Don't forget citrus are not just for your G&T. Try a slice of lemon in hot water for a healthy alternative to tea or coffee or try using sour Oranges and Kumquats in place of Lemons in your favourite recipes. Packed with vitamin C, all citrus are brilliant for keeping away winter colds but if you find them a little sour on their own, juice even the sourest Oranges with a bit of fizzy water and sugar and they make a super refreshing and healthy drink - way tastier than wheatgrass!
For more information about pruning, repotting and year round care click here