A giant cactus which just won’t stop growing has turned into a prickly customer by smashing the glass of a Lincolnshire garden centre greenhouse.

It happened at the Plant Lovers Nursery in Candlesby and was witnessed by partners Mink and Tim Sumner-Wilson.

They could only look on as the Giant Agave broke through the roof of their greenhouse.

And the native Mexican plant, nicknamed the Green Giant, isn’t intent on stopping there.

Since smashing through the 12-foot ceiling on March 29, it’s been growing at an incredible two inches a day at the nursery five miles east of Spilsby.

And it now needs a stepladder just to measure its full height of 14 feet and heading skywards.

Mrs Sumner-Wilson, 70, said the plant’s actions were part of the final stages in a somewhat tragic life - one that will see it eventually flower for the first time before dying shortly after.

“They are known by some as the ‘Century Plant’ because they don’t flower – or only flower once in a century,” she said.

“The flower stem is likely to exceed 25 feet, by which time it will have produced side branches that will produce numerous flowers.

“It will take most of the summer to fulfil its dream and then a further two years to die.

“This thing is going to be spectacular.”

The couple have run the specialist cactus nursery – believed to be the largest in the country – for many years and now have more than 20,000 plants.

And they reckon the Giant Agave, which they bought from a French nursery in 1968, is already between 50 and 60 years old.

“We were really surprised to see it flower,” said Mrs Sumner-Wilson.

“I really didn’t see it coming. I was talking to a visitor to the nursery when I glanced up at the greenhouse and realised that it had broken through the greenhouse roof.

“And I was surprised because I wasn’t expecting it to flower – I didn’t think it was old enough.

“They also usually alter in shape when they are coming up to flower and I didn’t think it had done so.

“We really didn’t think we were going to live long enough to see it happen.”

The pair will now allow the plant to complete its fateful final journey before repairing the damage to the greenhouse.

But, having been in possession of the plant for such a long period of time, it’s not going to be easy for them to say goodbye.

“Once it has finished flowering we will cut it so we can fit the glass back on, then we will probably leave it to die,” Mr Sumner-Wilson said.

“In that time it will produce off-shoots and we shall pop them up ready for sale.

“It’s become part and parcel of the family – so it will be very sad when it dies.”