It is fall and some gardeners are getting tired of their gardens. So what do they do? They go out and buy bulbs for spring flowers. For a true gardener there is always next year.
This post will walk you through the steps of how to buy bulbs and how to plant bulbs for a great spring garden.
Spring Bulbs – Understand How They Grow
A bulb is actually a complete plant. If you slice an onion in half and you get out your magnifying glass you will be able to see leaves, stems, flower buds and roots. They are all very tiny now, but the ‘package’ is ready to burst into spring leaves and blooms.
The bulb has been resting for the summer, not doing very much – botanically speaking. As temperatures drop, and the bulb absorbs moisture from the soil, it springs into action. First, it grows roots which absorb nutrients and more water. Then it starts making a new shoot. This shoot grows until it is just below the surface of the soil and then it stops growing. Ideally, all of this happens before the ground freezes for winter, but it does take time.
Not much happens during winter.
In spring, the shoot is right at the surface of the soil ready to make an appearance. That is why spring bulbs show up so early. The plant then flowers so that it can make seed. At the same time leaves form so that they can turn sun light into more plant food. In late spring and early summer the plant is busy sending food down to the roots where it is used to make a new bulb. The size of next years bulb depends on how much food can be made and stored by the plant. Bigger bulbs will give you a better floral display next year.
Making seed is the most energy intensive thing a plant does. It uses a lot of plant food to make seeds. Clearly, food that is used for making seed, can’t be used to make a bigger bulb – it is one or the other.
Understanding how a bulb grows will help you make smart cultural decisions in the garden.
Buying Spring Bulbs
Why would I have a section about buying bulbs? Don’t you just go into your favorite store and buy a bag? You can, but there are some things to keep in mind.
Since bulbs grow much better if they are planted early, you should also buy early. Get them as soon as they are available in stores. I stopped using one online service because they shipped bulbs too late in the fall.
In late fall you can get some great bargains – but are they really bargains? These bargain bulbs are more dried out than bulbs bought earlier. But more important than this, buying late means you can’t plant early, which means the bulb size the following year will be smaller. The bargain bulbs may mean you have fewer flowers for 2 or even 3 years, until the bulb gets back it’s lost energy. Is that worth it?
If you are buying bulk daffodil bulbs, buy very early and pick the ones with 2 or 3 bulbs stuck together. They don’t cost more, but give you 2 or 3 plants for the price of one. They get picked out quick so buy early.
Stroke That Bulb!
Touch each bulb in the pack. Give it a gentle squeeze, or stroke it if you like. If any bulb is not real firm, don’t buy it. Soft bulbs are starting to rot and will probably not grow.
When it comes to bulbs size does matter. A big bulb produces more flowers, or larger flowers and will make bigger bulbs in future years.
Growers sort bulbs according to size and then price accordingly. Bargain prices usually mean smaller bulbs.
Why Do Tulip Bulbs Only Bloom One Year?
This is a common complaint about tulip bulbs, but I am starting to see the same problem with newer fancy daffodil bulbs. They bloom great the first year, and then not very much in the second and subsequent years. Gardeners blame themselves – they must be doing something wrong!
It turns out that modern tulips have been bred for fancy colors and fancy shapes. They have not been bred for repeat blooming. They might grow fine the second year without flowers, but many types just get smaller and fewer each year. Its genetics! They no longer have the genes to come back year after year.
If you want tulip bulbs that bloom in subsequent years, get some old varieties from an old gardener, or buy a variety that is known as a rebloomer – like the Darwin tulip series. They are not as fancy – but they do bloom in subsequent years.
For daffodil bulbs – stick to the ‘less fancy’ types. Most of these still come back year after year and multiply fairly quickly.
When To Plant Spring Bulbs?
You now know how the bulbs grow and therefore the answer to this question is easy – as soon as you buy them. They need to make a good root system before the ground freezes.
What about spring bulbs that you dig out of the garden in mid-summer? Should you hold them until fall or plant them right away?
Most bulbs can be kept dry all summer and planted in fall. From the plants point of view there is no benefit to doing this, so you might as well plant them right away. The bulb is generically programmed to wait until fall before it starts to grow.
There are a few exceptions to this. Snowdrops (Galanthus nivalis) dry out very fast. Even sitting around dry for a week, harms the bulb. These should be planted right away. Some people say they should be planted “in the green” but that is a myth. For more details on this see Snowdrop – Should It Be Transplanted In The Green?
Digging The Hole
Depending on the bulb I am planting, I use two different kinds of holes .
For planting small bulbs, I like to dig a separate hole for each bulb. Because they are not planted very deep, I just use a trowel, stick it in the soil, move it sideways, and drop in a bulb or two – done. With this method you don’t actually dig a hole.
For planting large bulbs which need a deep hole, I usually dig one hole large enough for all the bulbs. Then I place the bulbs in the bottom of the hole, and cover the hole. This is faster than digging individual holes.
How Deep Do You Plant?
That depends on the bulb. The general rule of thumb is to plant at 2.5 times the height of the bulb. If the bulb is 2 inches high, plant it 5 inches deep. Sounds like a simple rule, but is the 5″ measured to the bottom or the top of the bulb? Turns out it is the bottom of the bulb ie the depth of the hole.
The planting depth is not that critical – you don’t need a ruler. Many bulbs have something called contractile roots. These are like springs that can pull a bulbs deeper if needed. Most bulbs will move up or down in the soil until they get to a point where they are happy.
When I dig up my daffodil bulbs they are almost always deeper than they were when I planted them. Muscari on the other hand seem to move up to just below the surface of the soil.
Plant Right Way Up
Most bulbs have a top and a bottom that is fairly obvious. The top is usually pointed, and the bottom tends to be flat. That is not always the case. Anemone blanda looks more like a little dog turd; black, hard, with no clear up or down.
How important is it to plant the right way up? Bulbs, like any other plant, can sense gravity. They know up from down and roots will grow down, and leaves will grow up. It does not matter which way around you drop the bulb in the hole. I’ve tested this and will publish the results on my GardenMyths.com blog this fall.
Sidenote: Anemone blanda is the only spring bulb I know that should be soaked in water for 24 hours before planting. It is very hard and the extra soak helps it to start growing. If you know of other spring bulbs that benefit from this treatment, let me know in the comments below.
Distance Between Bulbs
How far apart do you plant bulbs? This depends on your goals and to some extent on the type of bulbs.
What do you want the flowers to look like? Do you like the flowers spaced farther apart? Closer together? Each flower will end up above a bulb so space the bulbs to give you the spacing you want for the flowers.
Keep in mind that if the bulbs are happy in their new home they will multiply and get more crowded over the years. It is a good idea to give a little extra space for this growth.
The second point to consider is the bulb itself. Some bulbs don’t like to be too crowded. Daffodil bulbs don’t mind some crowding, but when they get too crowded they stop flowering. If you see this, you need to dig them up and give them more space. Other bulbs like the snowdrop seem to like being very crowded and it almost makes them flower more.
Spring bulbs tend to have their leaves grow straight up, and so neighbors don’t shade each other as much as most perennials. But tulip bulbs and to some extend daffodil bulbs have leaves that are wider and spread sideways – give them more space between bulbs.
I usually plant large bulbs 4-5 inches apart, and smaller ones 3 inches apart. Just eye ball it – don’t use a ruler.
Planting In Layers
Do you want more flowers from your planting hole? Plant bulbs in layers.
Remember bulbs are planted at different depths. You can plant some tulips or daffodils deep in the ground at about 6 inches. Then add some soil to partially fill the hole. Now add some small bulbs like Muscari (grape hyacinth), Anemone blanda or squil. You can even add species tulips to the top layer. Then fill the hole.
In the picture above, the yellow daffodils are planted deep, and the blue Muscari are planted shallow. Both types of bulbs have a soil area for their roots.
Depending on the bulbs you select, you will have one type of flower after the other which extends the flowering season, or you will have them flower at the same time – which can look quite nice. It is a great idea for smaller gardens where you want every inch of soil to perform.
Preparing And Amending The Soil
Is that clear enough?
Don’t add peat moss. Don’t add compost.These can make the soil around your bulbs too wet and bulbs like to be dry, especially in summer.
Whatever you do, don’t add bone meal. Unless you’ve done a soil test and have found that your soil is deficient of a nutrient, don’t add fertilizer. If you only need phosphate, use super phosphate in the planting hole, not bone meal.
Don’t put sand in the bottom of the hole – it does not increase drainage as many web sites claim.
Bulbs do not need a high level of phosphorus – that is a myth. For more about bone meal see Bone Meal Organic Fertilizer.
I grow hundreds of different types of bulbs, including about 80 different types of daffodils, and I have never fertilized them. I do mulch the soil surface with wood chips which adds some nutrients.
Defeat The Squirrels
Why do some people have squirrels that dig up their bulbs? I can’t say for sure, but I have always had squirrels in the garden and they never bother my bulbs. Here is what I do.
I don’t use bone meal which is known to attract rodents. Squirrels are just cute rodents!
When the hole is covered up I stamp on it and cover it with mulch. Squirrels will dig any place where they think other squirrels have buried food – they steal from each other. I make my newly dug soil look as if it was never dug.
I don’t plant tulips which seem to be a squirrel delicacy. But I do have a few regular ones and several species and my squirrels don’t dig them up.
I have a bird feeder and the squirrels can get some food there – maybe that helps?
The other approach is to plant bulbs squirrels don’t eat – like daffodils which are poisonous.
Spring Bulb Design
I could write several posts on designing with spring bulbs, but this is not the place for it. I just want to point out one important point. It is important to keep the leaves on bulbs as long as possible. As mentioned above, the leaves are feeding the roots which are making next years new bulb. The problem is that leaves on many spring bulbs don’t look great – Ok they can be ugly!
The solution is fairly simple. Plant bulbs like tulips and daffodils, which have large ugly leaves, near the center or even the back of the flower bed. In spring there will be nothing in front of them, and you can see the blooms. By early summer other plants grow up in front of the bulbs, and you will hardly notice the bulb leaves.
You can also select bulbs that do not have ugly leaves. Many spring bulbs have leaves that look like grass or are very small so they don’t show much. This list includes most smaller bulbs, including species tulips, dutch iris and Iris reticulata.
- Photo source: all images are by Robert Pavlis