Homegrown: Forcing Flowers

Lisa Slattery, Linn County Master Gardener, provided the following:

Are you stuck in the “winter-blah-before the crocus bloom” funk?  I am. I need something fresh in the house.  Forcing bulbs is an option if you choose the right bulbs but this year I want to try forcing branches of spring flowering shrubs.

 If you stick to flowers, choose Narcissus or paper whites. They are the easiest to force because they don't require a cold period.  Plant these in a pebble-filled tray (not soil) using a glass container for the tray and you can watch the roots grow too.  Make sure the upper-half of the bulbs are showing, place them in the pebbles and water thoroughly. Keep at about 60-65 F and you'll have flowers in 5 to 6 weeks.

 The Amaryllis bulb (known as the holiday bulb) is probably on sale now.  These bulbs require potting soil in a container that's 1 to 2 inches wider than the bulb. Plant with the top half of the bulb exposed.  Water thoroughly and place in a warm 70-75 F location. When growth starts, fertilizer every 2-4 weeks and you should have a very showy bloom in 6-8 weeks.  Tulips, daffodils and hyacinths require a cold period of 12 – 16 weeks, so I'd suggest waiting to see these in the garden. 

 In place of bulbs, I'm going to force some Forsythia and Pussywillow.  These can be forced as soon as the buds start to swell which is as early as February.  ISU Extension recommends waiting until March for more for more difficult-to-force ornamentals, such as crabapples, magnolias and redbuds.

If you want to try Forsythia and Pussywillow, select branches containing round, plump buds (which are flower buds not the narrow, pointed leaf buds).  Make clean, diagonal cuts about 1 to 2 feet from the tips of the branches with nice sharp hand shears.  If you are doing winter pruning, gather some of the pruned material to force indoors.  If possible, collect the branches when temperatures are above 32 F, if they're frozen submerge the branches in a tub or pail of water for a few hours first.

Place branches in a tall container of water, keep in a dimly lit, cool 60-65 F location and mist the branches two or three times a day to prevent the buds from drying out.  Change the water each day to inhibit the growth of bacteria and fungi.  When the flower buds begin to open, move the branches into a bright room, keeping them out of direct sunlight and in a cool location to prolong the bloom period. 

Time required to force branches will depend upon the plant species and collection date. Forsythia and Pussywillow should only take one to three weeks to force.  Magnolia branches could take three to five weeks.  ISU Extension suggests that the closer it is to the plant's normal outdoor flowering period, the less time it will take to force the cut branches indoors.

I don't have any Forsythia but my neighbors do and I'll be paying them a visit soon!