Naturalizing bulbs is quite possible if you take into account the specific needs of the bulb.
First Rule for Success
Bulbs must get the growing conditions they have in the natural environment.
They must not have leaves removed prematurely and in general, they must have a solid period of cold weather dormancy.
Second Rule For Success
The second thing you have to do is allow the seed heads to stay on the plant (again, don't mow them off prematurely).
Excellent naturalizing bulbs such as Scilla and Chionodoxa propagate from seed so if you want them to spread, you have to let those seeds mature on the stalk.
I note that no matter what you do in the garden the odds of getting hybrid tulip and hyacinth to develop seed, germinate and naturalize are long – it is a waste of time to try.
Third Rule For Success
Once you've agreed to leave the foliage, you have to decide where you're going to plant so the bulbs can naturalize.
The first thing is to give yourself space. The bigger the space the better when it comes to naturalizing bulbs and getting a swath of spring colour.
Large lawns are great for small bulbs.
Rocky areas are superb for the smaller species tulips.
Wooded or shady areas are excellent for bulbs such as
Allium ursinum (ramson),
Anemone nemorosa (wood anemone),
Erythronium dens-canis (dog's-tooth violet),
Corydalis cava (bulbous corydalis),
Fritillaria meleagris (snakeshead fritillaria),
Galanthus nivalis (common snowdrop),
Hyacinthoides non-scripta (bluebell), and
Ornithogalum umbellatum (common Star of Bethlehem)
My Daffodil Naturalizing
Fourth Rule For Success
The soil you're planting into also has to be appropriate for bulbs. Forget clay.
It holds far too much moisture over the winter and you'll have a death rate rather than a naturalizing bulbs bloomtime. Drainage must be excellent.
The soil is best when it is slightly acidic at a pH between 6.0 and 6.5 You can add peat moss to soil to increase the organic matter (beloved by bulbs) as well as drop the pH down (peat is acidic)
Gardeners with acid soils can use lime to increase the pH to the appropriate level. Most garden soils are already in the proper pH range in areas where bulbs can naturalize.
Fifth Rule For Success
Surprisingly, bulbs are like any other plant. If you want them to flower year after year, you have to feed them.
If you can only feed your plants once a year, do so immediately after blooming. Use a liquid feed like fish emulsion and water in all the bulbs generously.
Remember Doug's first law of gardening, “You only have to feed your plants if you want them to flower, grow new leaves or produce fruit.” Other than that – ignore them.
I know that some garden centres still recommend bonemeal but a little science might be in order here. Bone meal is a source of phosphorus. Phosphorus is almost immobile in soil. So unless you're planning on digging the phosphorus down to the level of the bulb roots, you are wasting your time and money on spreading it around the surface of the soil.
Simply scratching the soil surface and expecting the bone meal to get down another foot on its own is likewise not going to happen.
You can use a liquid feed to drive the phosphorus contained in the mix down to root level but that's about the only way you're going to get it there. Besides, bone meal is going to encourage dogs and raccoons to visit if you leave it on the surface.
Naturalizing bulbs can give you a massive display of spring blooming bulbs and a fun one at that.
Shopping Resources for this Page
A wide variety of flower bulbs and equipment from multiple vendors
Flower Gardening with Spring Bulbs Ebook
Doug's Ebooks Can Be Found Here