Mexican plant sleeps for 21 years then bursts through roof


A GIANT Mexican plant which lay dormant for two decades has suddenly sprouted a 6ft flower straight through the roof of one of Scotland’s most famous gardens.

Staff at the Royal Botanic Garden in Edinburgh were forced to remove a pane of glass to allow the Yucca elata space to grow.

The plant – known as a soap tree – grows up to five metres tall (16ft).

The plant was given as a seed to the garden in 1995 and waited until a fortnight ago to flower – adding an extra two metres to its height.


The Botanic Garden have been forced to remove a pane of glass to let the flower grow
The Botanic Garden have been forced to remove a pane of glass to let the flower grow


It comes just a year after St Andrews Botanic Garden was forced to remove a pane in their glasshouse roof to let an asparagus plant grow freely.

The soap tree was donated by Michigan University Botanic Garden and planted in Edinburgh’s ‘Arid Lands’ house in 1999.

The plant is native to Mexico’s two major deserts, the Sonoran and Chihuahuan, and it is thought that recent re-landscaping may have triggered its first flowering.

More air and light is reaching the flower which has resulted in one of the plant’s large spikes growing until it began pressing on the glasshouse roof.

Fiona Inches, glasshouse supervisor at the garden said the decision was taken to call in external workers and have the glass removed to give the soap tree the “best chance” of further growth.


The flower could continue to grow for another 4 weeks
The flower could continue to grow for another 4 weeks


She said: “It was a real surprise because we’ve had it for 21 years. We’ve recently done some re-landscaping, which might have resulted in more air and light getting to it.

“It is a bit late in the summer. It was a do we, don’t we situation. It’s never happened before so we thought we’d give it the best chance.

She continued: “It’s always a big deal when you have to take the glass out. It takes a full day. It’s not just a case of nipping up there and doing it, we had go get access guys in to help out.

“We’ve cut the glass slightly more than needed so that the rain comes down at an angle and misses the crown of the plant.

“Our computer regulates the temperature and so can cope with the changes and many of our plants are able to go down to freezing temperatures.

“It’s a great way to engage with people. It makes plants exciting as sometimes people just don’t notice them.”

The soap tree was used by native Americans to make baskets from its leaves which helped to collect the edible buds, petals and fruit from the plant.

The roots and trunk contain saponins, which are commonly used as a substitute for soap, hence it’s name.

And the plant is co-dependent with a species of moth called ‘Tegeticula yuccasella’ with neither the plant or the moth being able to survive without eachother.

The little white moth’s larvae depend on the seeds from the soap tree for food whilst the tree can only be pollinated by the moth.