Discarding a Christmas tree once the festivities are over always feels so wrong and wasteful - but it doesn't have to be this way.

If you want a more sustainable tree this year, you can opt for a container-grown variety which can be replanted after the baubles come down.

Pot-grown trees tend to be a bit more expensive and a little smaller, but you can grow them on in the garden or at least repot them so you can use them again next year.

"We need to double UK tree cover to help the fight against climate breakdown, and your Christmas tree can be part of this," says Emi Murphy, campaigner at Friends of the Earth.

"You can take the easy route and just buy a cut tree that you know will be taken off your hands and disposed of, hopefully chipped or made use of by someone else, but it is symptomatic of our throwaway culture, particularly around Christmas time," adds Friends of the Earth nature campaigner Paul de Zylva.

Ready to give it a go? Here is everything you need to know about buying a living Christmas tree.

Where can you buy a potted Christmas tree?

Many garden centres offer container-grown versions of the most popular Christmas trees - Nordmann firs, along with blue spruce, pine and other varieties.

For a change, you could even just use a potted shrub or miniature conifer indoors which you can plant outside after Christmas.

"A potted tree with roots lets you grow it outside and use it again, reducing its environmental impact and costing you less. A living tree will also carry on absorbing carbon from the atmosphere for years to come," says Murphy.

Container-grown trees have been grown for at least one season in their pots and it's often possible to lift the whole root system out of the pot and see the closely woven root which has grown in the pot, according to the British Christmas Tree Growers Association.

What should you look for?

The trees will be small, seldom more than 3ft, and should look fresh, the BCTGA advises.

They should be watered and cared for as for any houseplant - so kept moist (but not waterlogged) and away from radiators.

After Christmas they can either be planted out with a very good chance of success, or they can be left to grow on in their pot, but it is much better in this case to re-pot the tree into a larger pot.

The size of the tree will be restricted by the size of the container you re-plant it into.

What types of potted tree can you buy?

Nordmann fir Pot-grown blue spruce and Nordmann fir are widely available from good garden centres. Dobbies Garden Centres (dobbies.com) reckons the distinctive silvery-blue foliage makes blue spruce a stylish choice either on the doorstep or indoors for the festive season.

Their pot-grown trees are grown from hand-raised seedlings transplanted into growing pots plunged in the open field. Each pot is dotted with tiny holes which allow the finer tree roots to find nutrients from the surrounding soils, while keeping the main root system protected and intact within.

Nordmann fir can also be bought as a potted plant with excellent needle retention, a symmetrical appearance and strong, bushy branches and is ideal for those who want to put their trees up early.

The Norfolk Island pine looks like a mini Christmas tree and can be decorated accordingly, and also acts as a perfect foil for smaller, colourful houseplants such as Christmas cacti.

It can flourish either outside or inside throughout the summer months, but it's not frost-hardy so will need taking in during the cooler seasons and treated as a houseplant.

During new growth, it will offer a light green colour and then deepen to a darker green in winter.

Are there other non-traditional options?

Friends of the Earth suggests these other plants you could use instead of traditional trees which can be planted out or remain in their pots outside after Christmas.

Holly

Deemed by some to be the original Christmas tree, holly is evergreen so will be colourful even in December. Be careful of the spiky leaves though - if you're worried about children or pets you could take some cuttings to use as decorations instead of moving the whole tree indoors.

Bay tree

If you're creative, these evergreen shrubs can be clipped into stunning formal shapes and look fabulous framing front doors. You can also use the leaves (fresh or dried) in cooking.

Yucca

You may already have a yucca indoors and if you do, why not decorate it for Christmas? Large indoor plants like yucca trees look great with Christmas decorations on them.

What about artificial trees?

Paul de Zylva says: "If you've got a fake tree already, keep using it - make it last as long as possible. But look into a more environmentally-sound option when it eventually comes to replacing it."

When should I put up my tree?

If you're buying a real Christmas tree then you need to think about how long the tree will be up for.

Your tree should* survive for at least four weeks if it's a cut tree, but it will depend on how you treat it.

Lots of people already have their decorations and trees up (it seems to start earlier and earlier each year), but others like to wait until 12 days before. This will be Friday December 13 (the day after the General Election. What better way to celebrate?)

Once upon a time, trees were put up a lot later in the month, often in the afternoon of Christmas Eve.

Obviously if you have a fake tree, the answer is, whenever you want.