how to plant a bulb lasagne
To get dense and flowery spring pot displays, you have to try layering bulbs in what the Dutch call a bulb lasagne, layering them up one on top of another. The largest and latest flowering bulbs go in deepest, moving to the smallest and earliest in the top layer. The emergent shoots of the lower layer bulbs just bend round anything they hit sitting over their heads and keep on growing.
Done like this, you need to plant the bulbs slightly further apart than you would in a pot with a single layer so 1 to 11/2 inches apart is the right sort of spacing. The first layer can go as deep as 11-12 inches deep. Then cover them over with a couple of inches of potting compost, before you place the next layer of bulbs.
These combinations involve a two-layer lasagne, but you can push it to three, and branch out from just tulips to crocus, narcissus or hyacinths. I’m experimenting with this triple-decker this year.
For my deepest layer I’ve chosen the parrot tulip 'Orange Favourite' with huge, crinkly orange flowers, and the scent of freesias. It’s the last tulip to flower and invaluable for that. In the middle I’ve got a mid-season bulb, good, old, Tulip ‘Prinses Irene’ and I’m also trying out its newly bred sister, ‘Cairo’. This has the same silvery-green handsome leaves but is a deeper, richer colour. For one pot, my top layer is the famously reliable and handsome Narcissus ‘W.P. Milner’. The foliage appears in January in a sheltered spot and it can flower from February until April if you keep dead-heading. I’ve got another pot with the deliciously scented and delicate flowered March-flowering Narcissus ‘Minnow’ so I can compare which works best.
In my large Longtoms, (16 inches wide and 25 inches deep) I have fifteen bulbs in each layer, so forty five bulbs in the triple-decker, the bottom layer planted at nearly a foot, the middle at 8 inches deep and the top bulbs 4-5 inches below the compost’s surface.
As well as one variety flowering at once in one pot, I’ve been experimenting with mixing sycronized flowerers. I’ve had ‘Prinses Irene’ in my Long Toms mixed up with another couple of early ones - Tulip ‘Havran’ and ‘Couleur Cardinal’. The colours of the three works wonderfully together – I called it my Venetian Tulip Collection - black, deep red and burnt orange, all at their best at the same time.
Last spring I tried another trio of my current favourite tulip ‘Bruine Wimpel’, with ‘Jan Reus’ and ‘Helmar’. Tulip ‘Bruine Wimpel’ is incredible, the inside of its petals the colour of a brandysnap, the outside a mix of copper, chalk and pink and it looked magnificent planted with the deep wine-red ‘Jan Reus’ with a zing of boldness from the deep-red, flashed yellow ‘Helmar’.
This was an almost equal success to my Venetian group, looking good with bright, with healthy, springy foliage through March, topped with flowers for April into May. ‘Havran’ and ‘Jan Reus’ are both the tallest of their groups so they go in the deepest. Then comes ‘Prinses Irene’ , ‘Bruine Wimpel’, ‘Couleur Cardinal’ and ‘Helmar’ all about the same heights so it doesn’t matter which goes in which layer.
Large pot or little, in a group, or just one on its own, autumn is the time to plant your spring-flowering bulb fiesta.
watch how to plant a bulb lasagne
It is a pretty wet and miserable autumn day, so I have retreated inside because it’s bulb planting day. And I’m going to plant lots of pots today in bulb lasagnes.
And it’s the most brilliant system which you can never quite believe but the bottom bulb that is below perhaps one or two other layers of bulbs. If it hits its growth tip hits the bulb above it, it just goes round and carries on growing.
The other thing that I find incredible about this is that you think that the one planted most deep will be stunted so that the flowers will be all short and stumpy but that doesn’t happen, it’s incredible, it grows to the height that you would expect even if it was planted on the soil surface.
So, to do it, I have got this nice pot, which is about a foot deep, 30cms, a little bit wider, 40cm, and I am going to put lots of crocks in the bottom of the pot.
It’s slightly less important in a way, putting them in now, than you would with a summer pot because of course they create masses of roots. And the point of the crocks is it stops the roots blocking the hole in the bottom of the pot so stops drainage, but the thing is with bulbs is it just so important to have good drainage, so you have got to have your crocks in there. And now I am just going to fill with compost, but not fill, I’m just going to go to a depth, of 20cm from the top of the pot, so 18 inches. Not 18 inches, 8 inches.
And I’m going to do my first layer of bulbs. Now, I’m in fact using 3 different species. I’m going to use a tulip, a narcissus and an iris. And what you always have to bear in mind is that the smallest and earliest flowering bulb goes on the top, the biggest and the latest flowering bulbs goes in the bottom layer.
But if you are just planting as we do here, tulips in these layers, you can just mix them up in a tub trug or in a bowl or whatever you want to do. And you then just do them in the layers mix, so you don’t have to worry about the different depths but with me it’s the tulip that’s going in first because they are the biggest and they are the latest.
And then the next thing you need to bear in mind is the distribution or the concentration of the bulbs that you are planting.
So, in the garden, I would always do them at twice the width of the bulb so that’s the width, so its twice the width. But in a pot, you just want it to be much more concentrated, it is concentrated gardening, so I’m halving that. So, I’m literally doing it at the width of the bulb as a space between them and so in this layer, I can do six round the outside and three in the middle. And then, the compost just simply goes straight over the top and I’m coming up by about another 10cms.
Smooth that, and then in goes the narcissi. Same distribution.
And obviously, because I’ve come a little bit higher in the pot, I can get more in because it’s a bit wider as you move up the fluted pot.
And the great thing about this, is this will flower in March and the tulip will flower in April. And then I back fill again, and cover that.
And I’m coming right to the top now, and firm it down, and then just slotted in literally under the compost surface I’m going to do this iris. Which is an Iris reticulata and I completely adore these. And it’s because February is a really tricky month don’t you think, I always find it really tricky and we have had a long winter and spring is not yet there. But these iris really brings spring closer because they flower in February and, so I put them in pretty densely in the top of the pot.
There’s enough in these bags for two matching pots, and then I’m just going to spread them out over the compost surface so that I can see where they are before I press them in.
But I am putting them really pretty close and being quite generous and that feels quite extravagant but of course because they are in the top of the pot I can just, as soon as these are flowered I could leave them with their foliage, with the other things below them or I could just whisk these out as soon as they have flowered and store them until the following year so you know it is a one off purchase in a sense.
So I’m just going to put those nice and densely through the top and just ease them a little bit so they don’t fall over and then just do a final thin layer and that’s it, just label and wait for these to come up and as I say these are February, these narcissus are March and these tulips are April. And they are going to give me this lovely succession in a wonderful bulb lasagne.
general bulb planting tips
- Bulbs ideally suited to pot growth include Snowdrops, crocus, Iris danfordiae and reticulata, grape hyacinths, scillas, puschkinias, chionodoxas, anemones, hyacinths, narcissus (particularly the small-cupped and species varieties) and tulips (particularly the fosteriana varities (such as ‘Orange Emperor’ and ‘Purissima’), Single Earlies (such as ‘Prinses Irene’, ‘Couleur Cardinal’ and ‘Cairo’), Double Earlies and Triumph tulips (such as ‘Havran’)
- Drainage is key with bulbs, so all pots and containers need one of more holes in the bottom. These holes then need to be covered with crocks – pottery shards or pebbles – to keep the holes from being clogged with earth.
- In pots, you can plant your bulbs closer than you do in the garden. Even so, they shouldn’t touch each other or the sides of the pot.
- If planting just one layer of bulbs, plant at the same depth as you would in the garden – at a depth of twice their height at least (a minimum of 3 inches).
- Water on planting, and regularly in the first weeks when their roots are forming. Don’t let the compost dry out.
- Pots planted with spring-flowering bulbs can tolerate a certain amount of freezing weather, but will need some protection in moderate to severe periods of frost. Cover them with branches or circle the pots with bubble wrap to insulate.
