Layers of Tulips

Last year we saw a clip of Monty Don planting a deep pot with three layers of tulips. He had early, mid-season and late-flowing tulips, which he said would give a long-lasting display as each variety came up in succession.

I can't find the video now, but here's a clip of Monty demonstrating a similar concept only with different bulbs: How to plant a multi-layered pot of bulbs.

That seemed like a good idea, now that we live somewhere with a climate suitable for tulips. We ordered a selection of tulip varieties and planted them in three layers in a large pot (about 60cm tall). A few weeks ago the first half a dozen began to appear. But look what has happened now: 

I'm pretty sure that all three varieties have now reached the surface of the pot! If they all flower at once it will be a colourful display, but not long-lasting.