One of the great privileges I have with my garden writers’ hat on is that I get to go to sneak previews – and last night I went along to the unveiling of the new glasshouse at RHS Wisley, which opens to the public for the first time today.

Since I’m such a regular visitor to Wisley, I’ve been watching this amazing structure going up gradually over the years, and went along to another press bash in February to see it as the planting went in – well, then it was almost entirely under water after a winter of torrential rain, and we were all taking bets on whether it would be ready in time to open.

We needn’t have worried. It’s quite amazing what they’ve done in the four months since then: it still looks very “new”, and the planting outside (designed by Tom Stuart-Smith) is just in so will take some to show what it’s made of: but inside it is breathtaking. It’s going to be wonderful watching it grow over the months and years to come.

Here it is: a little stark, perhaps, until the exterior landscaping develops, but a remarkable structure nonetheless. It was designed in Holland, and doubles-up as a water collection system.

At the centre is a magnificent waterfall – you walk behind it as you pass from the temperate side into the tropical. The rock is artificial, and hides a “root zone” exhibit underneath.

There were orchids in the palm trees: I wasn’t quite sure if they were there for our benefit, or if they’re going to stay! They looked fantastic, anyway.

And then there were the plants… these Philodendron leaves were up to two feet long and that soft, velvety texture was so utterly gorgeous. And this is just a baby plant…

Outside in Cleve West’s teaching garden, there were loads of great ideas – I’m going to nick this fantastic birch-log path for the jungle area around my pond.