Shrubs, deciduous trees, the grass in your yard, evergreens, and the plants in your garden all adapt themselves to seasonal changes.
With a light-sensitive chemical, plants can sense the differences in day length. For example, in the fall, when the days start to get shorter, the trees sense that there is less sunlight. The plant is stimulated, and it sends messages telling the leaves to change colors and fall.
First, as the days shorten and the cold sets in, many plants become “hardened”. Water is pumped out of plant cells into the roots and any remaining sap, which is a sugary solution, often acts as antifreeze. Broadleaf trees, like maples and oaks, shed their thin, flat leaves each fall to reduce water loss.
Plants do not have calendars, but they can respond to environmental changes some being temperature, day length, and light quality. As the seasons shift, temperature and sunlight drive the chemical production inside the plant leaves. These different chemicals trigger different growth responses.
Warming in autumn delays senescence and, as a result, increases CO2 absorption by plants. However, plant growth in autumn is restricted by shorter day length regardless of warming, thus limiting the potential amount of CO2 absorption.
The growing season can be approximated as the period of time between the average date of the last killing frost in the spring to the average date of the first killing frost in the fall.
Because the enzymes driving biochemical reactions don't function well in winter, dipping temperatures and lack of sunlight slows plants' metabolism. Photosynthesis and respiration decelerate, and growth halts.
Perennials are split into further categories: herbaceous perennials die back to the ground in autumn and regrow in spring – examples include Verbena bonariensis, penstemon and ornamental poppies. Evergreen perennials keep their leaves all year round, such as some varieties of heuchera and hosta.
Biennials complete their life cycle in two growing seasons, often going dormant in the winter, then sending up new vegetative growth and flowers the second year before dying. The most famous examples are cole crops such as broccoli and cabbage, which we often treat as annuals in the garden.
Cool-season vegetables grow best in early spring or in late summer and autumn when temperatures are cooler. Warm-season vegetables grow best during the late spring, summer, and early autumn when the temperatures are warm.
In autumn when it starts to get cold, some plants stop making chlorophyll. Instead, those plants break down chlorophyll into smaller molecules. As chlorophyll goes away, other pigments start to show their colors. This is why leaves turn yellow or red in fall.
As night length increases in the autumn, chlorophyll production slows down and then stops and eventually all the chlorophyll is destroyed. The carotenoids and anthocyanin that are present in the leaf are then unmasked and show their colors.
While many crops won't grow during winter's coldest temperatures (say goodbye to melons, tomatoes, squash, and peppers, for example), many vegetables will tolerate and even thrive on the cooler temperatures that come with fall and winter.
Spring flower blooms, summer heat waves, freeze and thaw, growing seasons, and animal migrations are all examples of natural phenomena that follow seasonal patterns.
Known as Photoperiodism, indoor plants have their own response system that senses the natural changes in light, temperature, air quality, humidity, and overall environment. As the season moves toward fall and winter, it is common for most plants to shed their leaves as they prepare to adjust to the shifting season.
Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays. So, when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemisphere.
Perennial plants
These plants are ones that flower reliably every year. Usually get bigger each time. The stems die back over winter, but the roots don't.
Perennial. A plant that lives for 3 or more years. It can grow, flower, and set seed for many years.
Agave Americana Blooms Once Every Hundred Years
It's also known as a century plant because it only blooms once every 100 years (roughly) and then dies. But, because Raleigh gets more rain than the plant's usual home in the high elevations of Northern Mexico, the Century Plant is blooming after only thirty years.
Alyssum. Alyssum is a warm zone perennial plant, which means it can bloom all year in climates like California. It has small, fragrant white, pink or purple flowers and grows best in full sun.
The only plants that don't go dormant during the winter are annuals, which are only capable of surviving for a single growing season, and must be replanted each year for continual enjoyment.
Japanese yew (Taxus cuspidata) is a good choice for an outdoor winter plant because it's an evergreen that keeps its leaves on its branches all winter long. It's drought-tolerant and thrives in both full and partial sun. Hardy to Zone 4, Japanese yews can survive harsh winters.
Winter is coming. Trees, shrubs and other plants are slipping into hibernation, allowing them to survive the cold weather. They have gone dormant as they wait to be renewed in the spring.