Xtremehorticulture

Why Plants Get Confused Between Spring and Fall

Q. I have daffodils and Dutch iris bulbs shooting out new flowers this last November. Each year they produce leaves in the fall but never
flowers. Are they confusing this time of year with spring?  What should I do?

A. This type of oddity, flowering at the wrong time of year,
happens with some plants. Sometimes we see it in fruit trees like apples or
pears and even grapes. Plants are more in tune to their environment than
animals and these environmental clues can sometimes mislead them.
            Plants
that originate from temperate climates, climates with seasons, use two
major environmental “triggers” to gauge when to flower and produce fruit. These two
environmental triggers are cool or cold temperatures and unbroken darkness for
long periods. This works great in the spring.
            A
primary mission of plants is to survive and produce offspring
. Producing
flowers will produce fruit that produces seed. Spring flowering, not fall
flowering, is extremely important for temperate plants. Flowering in the fall
does not give most plants enough time to produce the seed needed for reproduction.
            If one
or both triggers are activated at the wrong time the plant may be “tricked”
into thinking it’s spring. Every fall the length of nighttime mimics the length
of nighttime in the spring. That’s one trigger. If there are unusually cold
temperatures in the fall, then both triggers could activate flowering.

What to
do? 

Remove the flowers when you see them. Otherwise, leave the plant alone.
Flowering in the fall is not a big deal but fall fruit and seed production is a
huge drain on plant food supplies needed for next spring.

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