Shrubs & Trees for Late Winter and Early Spring Forcing

from The Frelinghuysen Arboretum

The following table gives times to bloom for forcing branches of local trees and shrubs when cut at various dates.

Plant name Days to Bloom
if cut on ...
Normal
Bloom time

Expect

  1/28 2/15 3/15    
Abeliophyllum distichum – White forsythia 20 15 5 April 5 Flowers
Acer palmatum & japonicum – Japanese Maple - 20 10 April 5 Flowers/leaves
Acer rubrum - Swamp or Red Maple 20 10 6 April 5 Flowers/leaves
Amelanchier arborea – Serviceberry, Shadbush 25 20 15 April 15 Flowers
Berberis spp. – Barberry - 15 7 May Flowers/leaves
Betula spp. – Birches 20 15 5 March 25 Leaves
*Cercis canadensis – Redbud - 20 13 May 5 Flowers
Chaenomeles speciosa – Flowering Quince 25 20 10 April 20 Flowers
*Cornus florida – Dogwood - - 22 May 15 Flowers
Cornus mas – Cornelian Cherry Dogwood 20 10 5 March 25 Flowers
Corylopsis glabrescens – Fragrant Winterhazel 20 10 5 April 5 Flowers
Forsythia x intermedia – Forsythia 20 10 5 April 5-15 Flowers
Hamamelis x intermedia – Witchhazel 3-7 1-3 - Feb.-Mar. Flowers
Jasminum nudiflorum – Winter Jasmine 10 5 - Feb.-Mar. Flowers
Lonicera fragrantissima – Winter Honeysuckle 25 15 5 March 25 Flowers
Magnolia stellata – Star Magnolia - 15 7 April 15 Flowers
Magnolia x soulangiana – Saucer Magnolia - 15 7 April 15 Flowers
Mahonia bealei – Leatherleaf Mahonia - 20 7 March 25 Flowers
Malus hybrids – Crabapples - 30 20 April 25 Flowers
Pieris japonica – Japanese Andromeda 20 14 7 April 15 Flowers
Prunus spp. & hybrids – Ornamental Cherries 25 18 10 April 20 Flowers
Pryrus calleryana – Callery Pear - 20 10 April 15 Flowers
Rhododendron mucronulatum – Korean Rhododendron - 20 5 March 25 Flowers
Spirea prunifolia – Prumleaf Spirea - 22 12 April 15 Flowers
*Syringa vulgaris – Common Lilac - - 20 May Flowers/leaves
*Viburnum carlesii – Koreanspice Viburnum - 20 7 April 20 Flowers
*Weigela floribunda – Weigelia - 25 15 May 10 Flowers - 25 15 May 10 Flowers

*These may be more difficult to force. Keep humidity high by missing daily and/or cover branches with a plastic bag.

Cut branches should be soaked for a few hours to overnight in warm water. The easiest way to do this is to lay branches in a bathtub. Place branches in a clean container and fill with warm water, adding a floral preservative to keep prevent bacteria from forming. About every fifth day, thoroughly clean container, fill with fresh water and give the branches a new cut before placing them in the water. To clean the container, fill with warm water and ½ cup of bleach. Let the container soak about one hour, drain and rinse well before refilling.

The closer you get to the normal bloom time the faster the branches force. Please note that in warm years, plants will force much easier than in really cold winters. The number of days given is an approximation and length of time may vary.

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