Spring Flower Bulbs Grow too Soon

What happens if spring blooming bulbs such as tulips, daffodils, crocus, alliums, hyacinths and grape hyacinths start to grow too soon in the fall? Sending up leaves and maybe stems and buds too early? What if they are brand new – or have been there for years? Is it a problem? Will they survive? Will they still bloom next spring?

Grape Hyacinths and Autumn Crocus Should Grow in the Fall

First off, if you are growing grape hyacinths (Muscari — blue flowers in photo), take comfort in knowing that these little bulbs normally send up floppy green grass-like foliage in the late summer or fall. This is quite normal. Fall blooming crocus or colchicums also send up growth — and bloom — in the fall. Nothing to worry about.

Planting too Shallow Causes Fall Growth

Most spring flower bulbs such as daffodils and tulips may begin growing in the fall if they were not planted deeply enough. Flower bulbs should be planted, as a rule of thumb, down three to four times the bulb height. Use the deeper measurement in sandy soil, the shallower depth in heavier soil. This means digging a seriously deep planting hole and many of us are tempted to skimp. If your bulbs are sprouting and you planted them barely beneath the soil surface, you might want to gently dig them up (include any new roots growing downward below the bulb) and reset them deeper. Water thoroughly after replanting.

Planting in Warm Soil Causes Premature Growth

Another reason bulbs sprout unnaturally in fall is planting when the soil is still warm meaning above about 60 degrees. This could be due to planting way too early, or if unseasonably warm weather is causing higher than normal soil temperatures. Nights need to be consistently in the 40s F to cool the soil, so don’t judge your planting time by the calendar alone. If this is what is happening, hope for cooler weather soon. When it turns cooler, the growth will stop.

How and When to Protect or Cover or Mulch the Foliage

Once the foliage has emerged, what should you do? Generally, there isn’t too much you can do. When temperatures cool down, the top growth naturally stops. A little fall top growth should not affect flowering next spring.

Bulb foliage has good cold tolerance so frosts and freezes usually do no harm. Snow insulates well and protects against extreme cold, too. If you have no snow, apply a light-weight, non-packing mulch such as straw or oak leaves or pine boughs over the foliage in late fall. Remove it in early spring.

Possible Winter Damage to Flowers

In extreme cases, the bulbs progress so far that the foliage is fully formed. These leaves may discolor during the winter. Sometimes, they grow so much the flower buds show above ground. These exposed buds may be ruined by extreme low temperatures during the coming winter despite snow cover or mulching. But, perennial bulbs usually still survive.

Try Not to Worry Too Much

The overall message here is, wait to plant flower bulbs until both the soil and weather have cooled in the fall. If the bulbs sprout too early in the fall, do not panic. Hope for the best, nature is good at protecting her own. If snow cover is inconsistent in your area, toss a little fluffy mulch over the bulb foliage in late fall once the weather turns very cold. Enjoy your flowers next spring!

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