I have noticed an explosion of flowers this spring like nothing I have seen in many years, and I believe that one of the greatest botanical mysteries can explain the current abundance of blooms. This mystery concerns the connection between winter cold and spring flowering. The usual explanation give n is that a sufficient number of hours of winter chill – when temperatures are less than 45 degrees between September 1 and the end of March – are needed for a plant to break dormancy or open its flower buds. (In some plants, the number of flowers is also impacted by the extent or depth of winter cold.) With insufficient winter chill, some flower buds may still open, but the flowers will be stunted and unfit for pollination. The process of breaking dormancy generally refers to deciduous plants, from roses to apple trees, that lose their leaves in the fall or winter. Yet I have noticed evergreens such as azalea, Indian hawthorn (Rhaphiolepis spp.), Chinese fringe flower (Loropetalum chinense), and bird of paradise (Strelitzia reginae) flowering like never before. Moreover, I have seen my own semitropicals, such as wild gardenia (Gardenia thunbergia) and amole (Beschorneria yuccoides), flowering in recent days after being completely bereft of blooms last year. Rhaphiolepis umbellata blooms in spring. (Getty Images) Purple flowers of Loropetalum chinense rubrum shrub. (Getty Images) Amole Beschorneria yuccoides (Photo by Joshua Siskin) Show Caption1 of 3Rhaphiolepis umbellata blooms in spring. (Getty Images) Expand It so happens that the east San Fernando Valley, where I live, has experienced its coldest winter in years. There were 514 hours of winter chill this year, which is more than any year since 2018 – the earliest year for which I could find winter chill data – and more than double the number of such hours recorded in certain recent years. Should you want to check winter chill hours for your area, go to fruitsandnuts.ucdavis.edu/chill-calculator. In the list of weather stations provided, find the station closest to where you live and click it to reveal your winter chill hours each year since 2018. Once you have an idea of the range of chill hours in your locale, you can make informed decisions about which fruit trees to plant, since each kind has its own chilling requirement. Before selecting trees, vines or bramble bushes that yield fruit, go to the website of Otto and Sons, (ottoandsonsnursery.com), a nursery in Fillmore. The description of each fruiting tree, vine, and bramble bush in their catalogue includes the number of winter chill hours it requires. The horticultural importance of vernalization – cold exposure to induce flowering or other physiological processes – is not restricted to deciduous fruit trees. We know that most spring-flowering bulbs produce a greater number of flowers and/or larger flowers if they are refrigerated for at least one month prior to planting. Moreover, seeds of many species, especially those native to cold climates, require vernalization to germinate. The importance of cold in plant physiology is still shrouded in mystery, but the hypothesis is that cold dormancy prevents early onset of growth or development that would be disadvantageous to the plants involved. In the case of fruit trees and bulbs, without the requisite dose of winter cold, flowers may open early when weather conditions would not be optimal for pollination or when pollinating bees and other insects would not yet be active. In the case of seeds, dormancy prevents early germination before conditions are optimal for development of roots and shoots. Speaking of flower explosions, I was intrigued by “10 Ways to Embrace the Maximalist Style in the Garden,” an article that appears on the National Garden Bureau website (ngb.org: when you get there, click “Inspiration” at the top of the page to access the article). By way of introduction, I must extol this website, most of whose content is free. Trends in gardening are highlighted and a search box is available for access to hundreds of articles on both ornamental and edible plants and every gardening subject under the sun, from growing vegetables indoors to constructing a water pond to planting an orchard, with many, many discussions like this one on garden design. The maximalist style is bold and boisterous, creating unforgettable garden experiences. An exemplary maximalist garden would repeat a single color throughout, whether it was displayed in flower, foliage, or both. Take burgundy, for example. In this case, you would plant burgundy roses, especially since emerging foliage of roses is often burgundy around the edges as well. Hawaiian Ti plant (Cordyline fruticosa) and Cordyline cv. Burgundy Spire are famous for their burgundy foliage as is Kalanchoe cv. Pink Zinfandel, Kalanchoe sexangularis, Loropetalum cv. Red Diamond, Azalea cv. Little John, red Abyssinian banana tree (Ensete maurelii), and several coral bells (Heuchera) cultivars. An easy way to design with a maximalist style is to choose seldom-seen species to fill up your garden space. With the closure of so many niche nurseries from one year to the next, a garden of exotics is going to be that much more astonishing to behold. The repetition of a monochrome garden has no place here as the gardener’s gaze, to say nothing of garden visitors, is constantly interrupted as it moves feverishly from one botanical wonder to the next. Creating a number of garden rooms is a way of satisfying your craving for a combination of different maximalist looks. One room could be full of California natives or Mediterranean plants. Another, given that it had a half-sun to shady exposure, could be a fern grotto. Another could contain nothing but berries – strawberries, blueberries, and bramble berries. And then you could have an exotic fruit orchard in another room, or a room full of nothing but succulents and cactuses. The Getty Center garden in Brentwood is the quintessential maximalist garden and should be on the bucket list of every local plant lover. Admission to the Getty Museum and garden is always free, but entrance is by reservation only and you will have to pay for parking. Make reservations at getty.edu/visit/center/. California native of the week: There are quite a few California native species of coral bells (Heuchera spp.), although not all of them are typically encountered due to the highly specific habitat of some, especially those endemic to the Channel Islands. Many attractive Heuchera hybrids are available. Their maple leaf foliage can be found in lime green, gold, salmon, burgundy, purple, and a glittering gray with burgundy undertones. Heuchera, a ground cover, is notorious for being short-lived, an inevitable consequence of overirrigation. Yet if you just let coral bells grow and treat it with what is charmingly known as “benign neglect,” it can happily persevere for quite a few years at least and clumps may grow out to three feet across or more. I think the reason Heucheras flounder is due to too much shade. While not full-sun plants, coral bells will quickly die in excessively shady conditions. They are plants that benefit from bright shade, meaning they gladly absorb plenty of sunlight as long as it is filtered through the branches of overhanging trees. If anyone has a maximalist garden they would like to share with readers of this column, please let me know about it by sending an email to joshua@perfectplants.com. Your questions and comments, as well as gardening conundrums and successes are always welcome here. Related Articles Why home and garden fans will be interested in the Pasadena Showcase House We call them palm trees but they really are something else This colorful, hummingbird-friendly perennial never stops blooming Why you should consider planting dragon fruit in your Southern California garden What has been leaving empty snail shells in your shed? Probably rats.   ...read more read less