The Content Of The Article:
- Origin of phenology
- Pointer plants as indicators
- Gardening on the phenological calendar
- Picture gallery: Pointer plants of the phenological calendar
- Flowers under observation
Farmers rules such as "If the coltsfoot flowers, carrots and beans can be sown," and an open eye for nature are the foundation of the phenological calendar. Observing nature has always helped gardeners and farmers to find the right time to order the beds and fields. If you look closely, you can observe an annual, exact sequence of flowering, leaf development, fruit ripening and leaf coloration in the forest and meadows, but also in the garden.
Even a science of its own deals with this course of events: phenology, the "theory of phenomena". It covers the developmental stages of certain wild plants, ornamentals and crops, but also observations from the animal world such as the arrival of the first swallows or the hatching of the first cockchafer. From these natural phenomena derived then the phenological calendar.
The phenology distinguishes ten seasons. The beginning of each season is defined by specific pointer plants. The calendar as a phenological clock shows the middle beginning and the duration of the phases in Germany
Origin of phenology
The founder of phenology is the Swedish scientist Carl von Linné (1707-1778). He not only created the basis for the modern classification of plants and animals, but also created flowering calendars and set up in Sweden, the first phenological observer network. In Germany, systematic recording began in the 19th century. Today there is a network of about 1,300 observatories, supervised by volunteer observers. Often these are farmers and foresters, but also passionate hobby gardeners and nature lovers. They enter their observations in registration forms and send them to the German Weather Service in Offenbach, who archives and evaluates the data. Some of the data are evaluated directly for the pollen information service, for example the flowering of grasses. Long-term time series are especially interesting for science.
The peony is a classic pointer plant. At its bloom the phenological early summer can be read
Pointer plants as indicators
The development of certain pointer plants such as snowdrop, elderberry and oak defines the phenological calendar. The beginning and duration of its ten seasons vary from year to year and from place to place. In some regions, a mild winter causes early spring to begin in January, while in cold years or in rugged mountainous regions winter still prevails throughout February. Especially the comparison over the years makes the phenological calendar so interesting. Thus, probably as a result of climate change, the winter in Germany has become significantly shorter, the vegetation period on average two to three weeks longer. The phenological calendar also helps to plan gardening: with it, work such as sowing and pruning of various plants can be adjusted to the rhythm of nature.
Gardening with nature: Instead of relying on a specific date, one can also orient oneself to the development of nature. This overview shows which garden work should be done in which phenological season
Gardening on the phenological calendar
Instead of relying on a fixed date, one can also orientate oneself to the development of nature. If the forsythia blooms in the first spring, the best time for the rose cut has come. When the apple blossom of early spring breaks, the soil temperature is so high that grass seeds germinate well and the new lawn can be sown. The advantage of the phenological calendar: It applies in mild regions as well as in rough, and regardless of whether the season starts late after a long winter or early.
Picture gallery: Pointer plants of the phenological calendar
Start photo gallery
Pointer plants of the phenological calendar (17)
Early Spring: The flower catkins of hazelnut (Corylus avellana) are the first spring messengers. In many a year, the shrub flowers in January, but usually only in February. The shrubs prefer deep, humus-rich to loamy sandy soil. Not suitable are cold, heavy and wet soils
Early spring: The flowers of early bulbous flowers such as the snowdrop (Galanthus) show up in early spring. They appreciate shady garden areas under trees and larger shrubs. When planting a drainage is important so that the bulbs do not suffer from waterlogging at any time of the year. A 3-5 cm thick layer of gravel or sand, which is filled into the planting hole as a base, has proved its worth
Early spring: The crocus is also a pointer plant in the phenological calendar. Wild and autumn crocuses are ideal for frothing in lush lawns and sunny areas in front of early-flowering shrubs. Witch hazel, cornelian and winter snowball are well suited candidates here
First spring: The bluestar, here the Siberian Bluestar (Scilla siberica), is a classical pointer plant of the first phenological spring. Blue oysters prefer shady and partially shaded, fresh locations. They thrive particularly well in permeable, nutrient-rich soil
First spring: From March to April, the bell-shaped flowers of the Pasque Flower (Pulsatilla vulgaris) show up. When the flowering is over, the dry grass plant still enjoys a long time with its pretty feathery seeds. The pasque needs a humos-sandy, calcareous soil and lots of sun
First spring: The March beaker (Leucojum vernum), also a pointer of the phenological first spring, claims moist, nutrient-rich, moderately acid clay and loam soils, which as a humus form usually also contain gauze. The spring knot flower is a moisture indicator and colonizes locations up to heights of 1,600 meters
Full Spring: Apple trees open their flowers with the beginning of the full phenological spring. At the same time, the stalks of the winter cereal reach up in the fields
Full Spring: All lilacs are sun worshipers and tolerate dry heat. In shadier places, they also grow, but do not form a dense crown and use much less flowers. Noble lilacs are also very wind resistant, so they are often planted in northern Germany as windbreak hedges
Early summer: The peony (Paeonie) heralds the phenological early summer. The magnificent flowering plants prefer a full sun and a not too humus rich, loamy and nutrient-rich soil
Early summer: If the grasses are blooming, the phenological early summer will take hold. Then it's time for the hay harvest. Now begins the main flowering time of roses
Midsummer: hydrangeas (Hydrangea) bridge the somewhat low-flowering period of the phenological midsummer. The flowering shrubs need a sheltered, partially shaded place
Midsummer: While the grain is being cut on the fields, the redcurrants (ribes) are ready for harvest in the phenological summer
Late summer: Dahlias are pointer plants of the phenological late summer and like sunny, sheltered locations. Through the combination of different varieties you can achieve a flower splendor from June to October
Late summer: The last spring begins with the first early apples
Early autumn: In addition to the autumnal times (Colchicum autumnale) are in early fall, only a few flowers to see. For this, pears and hazelnuts are now ripe
Full autumn: Wild wine (Parthenocissus) grows in direct sun as well as in partial shade. It thrives best on moist, nutrient-rich soils. The plant also copes with slightly drier sandy soils. In lack of light, the leaves do not stain well in the fall
Late autumn: The leaves fall, the farmers do the last field work. If the oak sheds its leaves, winter begins
Flowers under observation
On forsythia, apple tree and snowdrop Gabriele Wenzel has a watchful eye in her garden. She notes carefully when the first flowers appear, the fruits ripen or the leaves fall in autumn
Gabriele Wenzel is one of about 1,300 volunteer "phenological observers" who form a network across Germany. The observers note how nature evolves over the course of the year in their respective region and report this data to the German Weather Service (DWD), which collects and analyzes the information.
Gabriele Wenzel has been an observer for 26 years. Her interest in the unusual activity was aroused in 1982 by a report in the news. "I'm a biologist, so it was easy for me to get into the matter." Among the phenological observers are many farmers, foresters and other professionals, but also many hobby gardeners and other nature lovers.
Part of the observations, such as the flowering of grasses, is given by Gabriele Wenzel as a so-called instant message, but most of the data is collected in her registration form and sent to Offenbach in autumn. Here, Ekko Bruns from the DWD coordinates the observations. "The phenological data are used for the advice of agriculture and the so-called pollen information service, a collaboration between the German Weather Service and allergy physicians," explains the scientist. The observations also provide valuable information for research into climate change: "Universities are becoming increasingly interested in phenological data, and requests to us are almost always related to climate change."
The results of the phenological observers reflect what the climate researchers predict in their forecasts: Spring begins more and more early, the autumn lasts longer. The changes in the phenological clock, which shows the changes over 40 years, are best shown. Ekko Bruns: "The phenological winter has been reduced by about three weeks, and the vegetation period has been significantly extended."