Telepeer

How the winter chill was cold enough this year to get this tree flowering

April 19, 2025

There is an Eastern dogwood tree (Cornus florida) — so-called since it is native to the Eastern US — at the end of my block, which I check on each spring to see if it’s flowering. I can happily report that it’s currently in bloom. It does not bloom every spring since it requires 400 hours of winter chill (temperatures below 45 degrees) to properly break dormancy with a flowery show . This winter, the North Hollywood weather station — which is closer to my residence than any of the other 273 such stations throughout California — recorded well over 400 winter chill hours, explaining the dogwood flowers I am seeing now. This is a highly desirable ornamental tree, with a mature height of about 20 feet in Southern California. Eastern or flowering dogwoods usually have white bracts, but this variety, known as Cherokee Chief, has bracts that are rosy red.

A week ago, I wrote about certain trees and shrubs requiring a specific dose of winter chill to bloom. A principal reason for lack of bloom is not just that flower buds don’t open when winter cold is lacking, but that flower buds simply do not develop. The development of an incipient bud into a flower instead of a leaf or shoot — whether we are talking about roses or plum trees — depends on a number of factors. Non-flowering buds are more likely to be present after insufficiently cold winters, and they are also more likely to be axillary or lateral buds, growing out of the side of a shoot or stem as opposed to apical buds that grow on shoot or stem terminals.

It is important to understand that plants exhibit two kinds of growth: vegetative (leaves and shoots) and reproductive (flowers). In nature, there is a balance between the two. Yet a plant has only so much energy to expend, and if conditions favor leaf over flower development, flower development will suffer. Excessive fertilization of any plant, especially where too much nitrogenous fertilizer is applied, will diminish flower production as this practice favors vegetative over reproductive growth. Nitrogen is a major constituent of chlorophyll, the pigment that makes leaves green and encourages a proliferation of foliage. Sun exposure is also crucial since plants have certain light requirements and a sun-loving rose bush or fruit tree will produce few flowers if planted where it gets less than four hours of sun, at a minimum. Ideally, fruit trees should get at least six hours of sun per day. Environmental factors such as too much or too little water, to say nothing of a drought, can also reduce flower bud formation. Finally, size rather than chronological age is crucial when it comes to flower development. A plant can be decades old yet, due to the absence of conditions conducive to growth, may remain stunted and flowerless. But now give that same plant the water, sunlight, and mineral nutrition it needs and it will put on an abundance of new growth and flower prolifically.

Getting back to the dogwood, both its common and Latin names are obscure. Some say dogwood is a variant of dagwood, with the “dag” a 15th-century abbreviation for dagger, referencing the hard wood of its stems that could be used for manufacture of this weapon. Alternatively, the “dog” in dogwood refers to the fruit, which, although edible, is of inferior quality and therefore, colloquially speaking, only fit for a dog. The Latin name of Cornus is cognate with horn, implying that its wood is as hard as an animal’s horn. Cornus is also a word derived from the Greek word for cherry and refers to the fruit of the Cornelian cherry (Cornus mas), which is bright cherry red, even while more elongated than conventional cherries. Speaking of botanical names, the species of dogwood in my neighborhood is florida, a Spanish word for flowery. This name was given to the land that eventually became the eponymous state by Ponce de León. The Spanish explorer arrived there during the spring of 1513 and named it La Florida (the flowery one) due to the abundance of flora in bloom at that time. The only other dogwood tree I have seen locally is in the garden of Loren Zeldin in Reseda. He has a shrubby tatarian dogwood (Cornus alba), which sports clusters of white flowers on shiny red stems and twigs.

Pink trumpet tree Handroanthus impetiginosus flowering before leaves appear. (Photo by Joshua Siskin)

I have recently noticed four deciduous trees with pink flowers that bloom in late winter or early spring before any leaf buds open, making them especially memorable arboreal fare. One of these is saucer magnolia (Magnolia soulangeana), a small tree whose petals, when they flatten out, resemble saucers. The California native Western redbud (Cercis occidentalis) is another early blooming pink (to magenta) beauty; both it and the saucier magnolia are memorable for sullen grey bark that contrasts perfectly with their cheerful flowers. Then there are the pink trumpet trees (Handroanthus impetiginosus) blooming along Ventura Boulevard in Sherman Oaks that simply take your breath away. Yet the most spectacular display of pink-flowering trees may be seen at Lake Balboa in Encino. The collection of Pink Cloud cherry trees — strictly ornamental and not grown for fruit — that surround the lake are a wonderful gift to those who look to trees as harbingers of spring and the birth of another season of flowering, nurturing, and growth.

California native of the week: Red osier or creek dogwood (Cornus sericea/stolonifera) is more water needy than most of our indigenous plants. But perhaps its unique decorative elements entitle it to a longer drink of water than other natives. It also needs protection from the afternoon sun. Bright, wine-red stems are its outstanding feature, especially noticeable when leafless in winter. These stems grow up to 15-feet tall in an aggressively spreading, rhizomatous clump. They make a fine boundary to a lawn, although you will want to install a root barrier so that the dogwood stays on its side of the lawn. Before dropping from the plant, leaves display a kaleidoscope of fall colors. Its bracts or modified leaves (commonly mistaken for flowers on all dogwood species) are white. The Silver and Gold variety has foliage variegated in green and silvery white along with golden yellow stems.

Do you have any flowering trees to recommend? If so, tell me about your favorite(s) in an email to [email protected]. Your questions and comments, as well as gardening conundrums and successes, are always welcome.

How the winter chill was cold enough this year to get this tree flowering Orange County Register

News Details

How the winter chill was cold enough this year to get this tree flowering

Leave a Reply Cancel reply

News

CONTACT INFO

QUICK LINKS

SERVICES

CURRENT NEWS