Growing citrus trees in a cool climate?

If you’re dreaming of sunnier climes, a citrus tree at home may provide a little respite.

The chances are, if you’re lucky enough to have a garden with a fruit tree in it, that fruit tree will be some variety of gnarled apple. It will reliably keep you in good supply for crumble, and your garden will be awash with wasps drunk on fermenting sugars come late summer.

Plum and pear trees also vye for pride of place, but how many of us – dealing as we do with Britain and Ireland’s cool, changeable weather – would consider growing citrus? And would it work if we did?

With the option for summer holidays still looking dubious, a lemon tree might just bring the sunshine we so desperately need…

So why should you grow citrus?

“Because it’s fun,” says Amanda Dennis, partner at The Citrus Centre. “The flowers, the fruit, there is nothing better than picking your own lemon or lime off your tree. The flavour in the skin and the fruit is far, far superior to anything you buy in the shop. They’re all unwaxed and you get all the lovely natural oils in the skin. And they’re much fresher – to me, shop-bought fruit tastes insipid, because shop bought fruit has been sitting around for weeks. Whereas when you pick something directly, even eating orange peel, which you wouldn’t do with an ordinary orange, is different.

“You get all the lovely fragrance from the fruit, and then you have the lovely fragrance of the flowers as well.”

Are they easy trees to grow?

While we can’t compete with growing conditions in the Med, or California, Dennis says citrus trees aren’t rocket science to grow here. The key, she says, is where you place them. “You need to have somewhere with lots and lots of light, that’s frost free for the winter, so, a heated greenhouse, heated conservatory – perfect,” she says, “but we have many customers who keep them next to patio doors or on windows sills.” Then you can pop them outside during “the warmest parts of the summer”, in June, July, August and September.

It sounds like citrus in pots are the best option?

“They’re better kept in a pot than planted into the ground, so they can be moved indoors in the winter,” notes William Mitchell, owner of Sutton Manor Nursery..

“Always in pots – and always in plastic pots,” confirms Dennis. “Terracotta is a nightmare for most things, but the drainage on terracotta is terrible, and citrus don’t like wet feet.”

Can you grow them in a small space?

“All citrus trees can be planted in a small space, however, the bigger the fruit, the more space it will need,” says Mitchell. “Standard citrus trees should be placed 12 to 25 feet apart, and smaller ones should be six to 10 feet apart.”

Do they appreciate companion planting?

Some people swear by keeping herbs like marjoram and oregano nearby, while Mitchell suggests companion planting a lemon with other citrus trees, “such as kumquat and lime trees”.

Dennis, however, doesn’t opt for companion planting. “No. We don’t do that,” she says. “We don’t have anything that competes with the roots.”

Could you grow trees from seeds taken from supermarket citrus fruits?

The simple answer is yes, although “this can be a lengthy process and it could take anywhere from five to 15 years for the fruit to bear,” says Mitchell, who adds: “When it comes to planting, you will want some high-quality soil. Once you have this, spread half of your seeds over moist soil, then sprinkle a half-inch layer of seed raising mix over the seeds, and lightly tamp the soil.”

If you’re brand new to citrus growing, where’s good to start?

“We always recommend lemons and limes for beginners,” says Dennis. “The orange we recommend is the Calamondin orange, which is a little sour orange. Those three are really good beginner’s plants, and flower and fruit very readily.”

What about kumquats? They’re really popular and often suggested for beginners…

“No! Kumquats are really difficult to bring into flower and everybody makes that mistake, because they are one of the hardier of the citrus, but they take a lot of heat to bring them into flower,” explains Dennis, noting they’re one of her favourites to actually eat. “They have to stay indoors through the summer, and the trick with that is not to roast them to death, which is why they’re difficult.”

How about if you do have a little citrus experience?

“We have something called an Ortanique, which is an orange-tangerine cross. They flower quite easily. Mandarins and satsumas flower better than an orange, an orange is quite difficult,” muses Dennis. “But grapefruit flower quite easily. Clementines definitely will flower; clementines and satsumas – the satsuma family – will always flower much more easily than an orange.”

How do you know when to pick the fruit?

“Lemons and limes can be picked any time, regardless of whether they’re yellow or green, once they’re fully sized,” says Dennis. “Clementines and satsumas are normally ready around Christmas time. That’s why you always get lots of them in the shops at that time of year.

“Oranges and grapefruits are slightly more difficult, because they can take a year to 18 months before they’re ready. And you generally don’t get a lot of fruit on an orange or grapefruit. So that is more tricky, because once you’ve picked it, if you’ve only got a couple and it’s not ready, you’ve got to wait a few more months until it’s ripe.”

Is there anything else people should absolutely remember when they bring a citrus tree home?

“Light is really, really important for the winter, so wherever they keep them, it has to be light and frost free,” says Dennis, who adds: “Feeding and watering is the key to keeping any citrus. They hate their feet being wet for a long time – as do we humans. I always say to people, ‘Well, if you had your feet in a bucket of water for a week, what do you think they’d look like?’ That is exactly the same as most plants – unless it’s a bog plant!”

For citrus trees and further advice visit fernhill.ie; johnstowngardencentre.ie; clarenbridgegardencentre.ie