Planting a bulb lasagne will help you cook up the recipe for successional blooms in your garden.
A ‘bulb lasagne’ is the name sometimes given to layering bulbs, either in a container or in a planter or small raised bed.
Largest, latest flowering bulbs go in the deepest layer of your lasagne, with more, earlier flowers above them, up to the earliest flowering bulbs near the top.
With two tiers of bulbs, this is sometimes called ‘double decker’ planting. However, you can sometimes stretch this and have three layers (and occasionally even four).
This is a simple gardening job that you can enjoy with children. It is very easy whether you are a complete gardening novice, or someone far more experienced looking to try out some new combinations or varieties of bulbs.
The Purpose of a Bulb Lasagne
Just as layering plants above the ground is a great idea to make the most of your space, so too is layering bulbs below the soil (or potting mix).
Layering bulbs in the same container can help you make sure that you make the most of your space and have flowers for visual appeal (and for bees and other pollinators) over as long a period as possible.
By layering spring (or summer) bulbs, corms and tubers in pots, you can ensure that the flowers bloom successionally. You can choose your bulbs carefully so that each flower is coming into bloom just as the latter begins to fade.
Spring bulbs are particularly useful in a garden, because they can often provide early blooms when there are few other flowers around for pollinators. They can also fill in gaps in an ornamental planting scheme before summer flowering plants take over the display.
Where to Place a Bulb Lasagne
A bulb garden is usually made in a large plant pot. The larger the pot, the greater the impact can be.
But it is worthwhile considering that you could also layer bulbs in a planter or raised bed in a small garden.
When choosing where to position your pot or create your bulb lasagne, it is important to think about which bulbs you will be growing (or the space available). Be sure to think about sunlight, shade and other environmental factors.
Many spring bulbs prefer a sunny spot, but there are also bulbs suitable for more shady conditions.
Choosing Plants for a Bulb Lasagne
When choosing bulbs for layered planting, the first thing to think about is where they are to grow and the environmental conditions to be found there.
Once you have considered the basics, you need to decide which bulbs you would like to grow. There are a number of factors which might enter into your decision. For instance, flower shape, colour and size.
But one of the most important things to consider is when each of the bulbs you are considering will flower.
Remember, the goal is to find different bulbs, and to plant them in layers in the same space so that they will bloom over as long a period as possible.
Largest, latest flowering bulbs for a bulb lasagne include:
Medium-sized bulbs to be planted above those might include:
- Daffodils and other Narcissus
- Earlier Tulips
Small, early bulbs to plant closer to the top of the soil or potting mix include:
- Glory of the Snow (Chionodoxa)
- Grape hyacinths
- Miniature Irises
Choosing a Suitable Container
The size of container required will depend on which bulbs you would like to grow, and also, of course, how much space is available.
Typically, however, the larger a container you can manage, the more effective and dramatic the display will be. Spring flowers often look best when grown in clumps or drifts with as many of them as possible.
In terms of depth, you need to make sure that you have the space to accommodate the planting depth of the bulbs on your lowest tier, plus at least 10cm below that for their root systems.
Typically, a pot or container at least 50cm deep and 50cm wide will be best. Though with some bulbs, you will not need such a sizeable container.
Remember, when thinking about containers, that you do not necessarily have to buy containers for the purpose.
If you use your imagination, you will soon see that there are a range of reclaimed materials and items that you could reuse in your garden.
Choosing Your Growing Medium
Bulbs do not require anything particularly fancy when it comes to the growing medium. A general multipurpose compost is usually fine. Just make sure, for environmental reasons, that you choose a peat-free option.
You can also consider making your own potting mix with ½ homemade compost and ½ garden soil, which should be fine for most spring bulbs. Just make sure that your mix is relatively free-draining, or your bulbs may rot.
You can also consider adding other homemade materials like leaf mould to the mix.
When To Plant a Bulb Lasagne
You should sow spring-flowering bulbs in autumn. In September or October, choose your seeds and get a pot or container ready.
One thing to note is that you do not need to leave your container bare with just bulbs under the soil during the winter months – you can consider adding winter bedding plants (like pansies, for example) to the top of the containers until the first bulbs begin to emerge in late winter or early spring.
How to Plant Your Bulbs
- Prepare your pot, container or planting hole. Place crocks at the base of a container to aid with drainage.
- Add a peat-free multipurpose compost to your container (make sure there are at least 10cm of potting mix below the first layer of bulbs for their roots to grow into).
- Place your first layer of bulbs, each around bulb width apart and facing upwards. Try to identify the top and root end of each bulb. With some bulb types this can be challenging, however, so if you are not sure, place them on their sides and they should still grow upwards towards the light.
- Cover these first bulbs with a thin layer of compost then place your second tier of bulbs. Try not to place the bulbs in this layer immediately above the ones below. Use a different layout pattern for each tier if possible.
For example, you might plant a ring of allium bulbs. Then place daffodil bulbs in the centre of this ring for the second layer. Then add crocus around the edges of the pot.
The crocus will flower first, then the daffodils, then the alliums just as these begin to fade, giving a longer-lasting display.
- Repeat this stage if you are adding a third and perhaps fourth layer.
Note that, as a general rule of thumb, you should aim to add your layers so that each bulb is planted at around 3 times its own height in depth. So start your first tier at the right depth below the finished soil surface for the bulbs you have chosen.
Make sure, also, that you layer the bulbs in the order in which they are to flower.
- Bury the top layer of bulbs with around 10cm of soil.
- Then top with a layer of horticultural grit to ensure good drainage. Or add overwintering bedding plants to the pot to make use of it over winter while bulbs are still not throwing up shoots.
As you can see from the above, it is very easy to create a bulb lasagne, you just have to bear a few simple things in mind.
Make sure you keep your container moist but not soggy throughout the flowering period. Take care not to overwater, especially over winter, or rot could set in. And keep your eyes peeled for pests.
A well-planned and not overly crowded scheme may continue to flower well in your container for two or three years, after which you will likely have to extricate your bulbs, thin them, and re-pot them in new containers.
If you are adding bedding plants to a container of layered bulbs, be sure to replace the top layer of compost each time you change out the bedding specimens.
As you can see from the above, layering the bulbs correctly is the main trick to success in creating a bulb lasagne. As long as you get this right, you should be pleased with your displays.
Play around with different spring-flowering bulbs to work out the perfect combinations, and have some fun thinking about new combinations of bulbs to try.
A permaculture garden designer, sustainability consultant and freelance writer, Elizabeth works as an advocate for positive change. She aims to inspire others to reconnect with nature and live in a more eco-friendly way. She also tries to practice what she preaches as she tends her own forest garden, polyculture beds and polytunnel. See her personal website here.