Bulbs - Everything You Need To Know


Planning Your Bulb Display

Spring bulbs bring wonderful color and variety to gardens and landscapes after winter.  Early-flowering Crocus, Snowdrops and others welcome spring.  Following these up with Tulips, Narcissus, Allium, Iris, and many others provides color and enjoyment to early summer when other garden flowers take over.  Depending on your landscape and space, bulbs can be utilized in a variety of ways. 

Adding to Existing Beds and Borders
Bulbs bring early spring color to gardens whose perennials have not yet started growing, and before one can even consider annuals.  For those with space and ambition, a mass planting of bulbs in a bed, which could then be used for annuals, is stunning.  However, unless you’re willing to wait for the bulb foliage to die back, this would have to be done annually.  This allows you to change the layout and try new bulbs each year.  On a more moderate scale, integrating bulbs into existing beds gives early color and bloom.  Ideally, plant bulbs in groupings, so that they can have the most impact.  Typically as the bulbs’ foliage is dying down, the emerging garden plants will mask it from view. 

Naturalistic drifts of bulbs such as daffodils and crocus look lovely in lawns, along woods’ edges and in other appropriate landscape settings.  The key to these plantings is to avoid harsh edges so that the bulbs look like they sprang up naturally.  Varying the density of the planting can help with this, and it’s especially important to “feather” out the planting to soften the edges.  Over time, the bulbs will spread themselves and make the display even more natural.  Bulbs especially well suited for this include Narcissus, Crocus, Chionodoxa, Winter Aconite and Scilla.  Galanthus, Leucojum and Dog-tooth Violets are also good for naturalizing in woodland settings.

If you’re planting in turf areas, it’s important to remember that the bulbs need to retain their foliage after bloom.  Therefore, it’s best to plant the earliest flowering bulbs so that they will have time to bloom and grow foliage to produce nutrients for the bulb before it’s time to begin mowing the turf.

Bulbs can be lovely in containers, inside or out. Good bulbs for indoor forcing include large flowered Crocus, Hyacinths, Grape Hyacinths and Iris reticulata.

Indoor Forcing:  Forcing bulbs for indoor planters merely requires appropriate chilling time to induce the bulb to bloom.  Choose bulbs said to be good for forcing, such as Crocus and various Daffodils.
1) Store bulbs prior to planting in a mesh or ventilated paper bag in the refrigerator.
2) When potting, allow for 2” of soil beneath the bulbs in the pot.  Plain potting soil   works fine, and make sure the pot is large enough to have the bulb tops even with the  rim.  Bulbs like to be pot-bound and cramming them together in a pot usually produces   the best display when they bloom.
3) Chill the pots for at least 12 weeks (either in a refrigerator or other cold,   non-freezing spot, then bring into indirect sunlight and temperatures of ~60F for 1-2 weeks.
4) To induce bloom, when shoots have gotten 3-6” tall, move the pots to a bright, sunny   window, ideally with a temperature of 68F. 
5) When buds take on color, move pots back to indirect sun – this will help the blooms last  longer.
6) At all times, keep the soil moist.

Note – Paperwhite Narcissus and Amaryllis do not require this chilling regimen.

Outdoor Containers – If you have larger pots that you’d like to use for displaying bulbs, you can plant them up in the fall and store them in a cool, dark, non-freezing place.  Then bring them out in spring for their blooming.  Spring-flowering bulbs come in a wide range of sizes and colors, so you can choose flowers you like. Experiment with new varieties, find ones, which are fragrant, choose ones to use as cut flowers . . .whatever your interest, and there are probably a variety of bulbs that fit.  Figure out what works best for your space and your taste and start planting.

Tools and Rules
Whatever tool suits you is the best tool to use, and there is a variety.  Bulb planters can be very effective, and the long-handled ones reduce some of the stress on backs and knees.  Trowels and shovels are tried and true.  All work, just make sure to get good quality tools, and unless your soil is tilled and fluffy, sharpening the edges can be helpful.  As for rules, there aren’t many.  First, while bulbs are very accommodating to a variety of settings, they all need good drainage.  Make sure the site you’re planning on has this, and ideally the soil should be rich in organic matter.  The soil’s pH is also important, and should be between 6-7.

When should you plant?
Bulbs produce best root growth when the ground temperatures remain between 40-50° F for several weeks.  In our zone, this generally means that planting by mid October is ideal.  You can plant later than this, so if you find some bulbs left out in the garage or shed and forgotten, don’t despair – go ahead and plant them!

How should you plant?
In general, plant bulbs at a depth of at least 2-3 times the height of the bulb.  Or, even simpler, plant small bulbs such as Crocus and Scilla 4” deep, plant larger bulbs such as Tulips and Daffodils at least 6-8” deep.

How should you fertilize?
Mixing in a little bulb food at the time of planting is helpful. Naturalized plantings also benefit from an organic bulb fertilizer in the fall. Then, when the shoots first start to emerge in spring, (usually about 6 weeks prior to bloom), fertilize with a higher Nitrogen fertilizer to help the foliage grow and produce food for the bulb.  

Should you mulch?
Mulching is beneficial both from an aesthetic and a cultural standpoint.  However, it’s important not to mulch until the ground cools down (just before it freezes).  Then, no more than 3” of mulch will help retain soil moisture and also keep ground temperatures cool and stable.  

After Bloom – Remember, bulbs need their foliage to produce nutrients to be stored for next year’s bloom – so don’t disturb the foliage until it has died back on it’s own.  Don’t cut it back, don’t braid or tie it up, just let it alone for best results.