Weather plays an important role in many gardening activities. Meteorologists’ weather forecasts are now quite reliable, but even more reliably, so-called weather plants can tell you the weather for the next few hours.
Garden plants as weather prophets
Weather plants, often called weather prophets, are certain species that are particularly sensitive to changes in the weather – especially in the areas of humidity and heat. If these rise or fall, visual changes appear on the plants. These must be recognized in order to make a reliable forecast for sunshine or rain in the following hours. In most cases, it is sufficient to look at the flowers. In some cases, the weather can also be determined by the scent of the plant or flower.
Weather plants at a glance
Long before you notice a slight but continuous increase in humidity, birch trees (Betula) begin to notice an odor effect. They increasingly begin to give off a spicy odor. The more humid the air becomes, the more intense this becomes. If you notice this, there is a high probability that rain is coming.
The Christmas rose (Helleborus niger) presents itself as a special weather plant. Already in grandma’s times the flower buds were used to determine the weather for the following month. To do this, a bud is cut off, placed in a glass of water and placed in a warm, bright location. If the bud opens, a sunny month is expected. If the bud remains closed, expect a lot of rain.
According to an old tradition, it should be possible to predict in this way how rainy or sunny each month will be for an entire year. To do this, twelve buds are placed in a glass of water on Christmas Day, each one representing a particular month.
If rain announces itself by increasing the humidity, lady’s mantle (Alchemilla) quickly begins to “sweat”. This can be seen by the formation of dew. Small drops of water make their way onto the stems and occasionally onto the leaves.
One of the most weather-sensitive plants is the daisy (Bellis perennis). It prefers dry air and begins to raise its petals at the slightest increase in humidity. In this way, the daisy prepares for impending rain and protects the flowers by closing the petals.
Gazania / midday gold
Midday gold, as gazanias (Gazania rigens) are also called, is very picky about opening its flowers. When petals slowly spread apart, sunshine is usually within “reach”. If the leaves remain in one position while opening, no further change in weather can be anticipated for the time being. If the leaves close completely again, heavy cloud cover is imminent. Rain in this case is not necessarily predetermined, because lack of sun is already enough for the closure of the flower.
Cape Basket / Cape Marguerite
Cape corms (Osteospermum), also known as Cape marigolds, Bornholm daisies and paternoster shrubs, reliably let you know if it will start raining promptly. Its flowers open this weather plant only when the sun shines. However, it takes a significant rise in humidity before it “ramps up” the petals for wear. If you see this condition on Cape marigolds, you can assume that rain is imminent.
A weather forecast can be made by the flower direction of mullein (Verbascum). If the flowers face east, the sun is not far away. However, if they turn to the west, they predict rain soon. If leaf rosettes have formed on mullein in the first year, you can even find out how early or late it will snow in winter. To do this, check the leaf density. If this is clearly in the lower range, the chances of an early snowfall are high. If the leaves have grown densely in the upper range, a white Christmas is likely to be cancelled and it will not snow until January.
Similar to birch trees, linden trees (Tilia) can be predicted for weather changes. They also react early by intensifying a noticeable odor. However, only the flowers of lime trees provide the scent. This is delicate, cool and exudes a slightly sweet note. If a thunderstorm threatens in warm air conditions, the flowers reach the maximum fragrance intensity. This can then already be smelled within a radius of 20 to 30 meters.
Like numerous other flowering plants, dandelion (Taraxacum sect. Ruderalia) closes its flowers in time before dark clouds gather and it begins to rain. By the way, dandelion is also one of the so-called indicator plants, because its wild growth indicates very heavy and nitrogenous soils.
Carrots / Wild carrots
By the characteristics of wild carrots (Daucus carota subsp. carota) you can predict the weather, especially in midsummer. At that time, the plants have many seed umbels. If a rain front approaches, these bend inward. Widely standing and straight up seed cones indicate sunshine for the next few hours.
Night violets / common night violets
If night violets (Hesperis matronalis) are particularly fragrant, rain is approaching. As a rule, cruciferous plants react comparatively late to increasing humidity combined with warmth. As soon as the aromatic scent intensifies significantly, it won’t be long and it will most likely rain. If little or no fragrance is perceptible, it will remain dry.
With marigolds (calendula), rain is quite easy to predict. They close their flowers. Often this happens hours before the rain begins. You can still do various gardening tasks.
There are over 700 different species of wood sorrel (Oxalis) worldwide, and each one is considered one of the most “intelligent” weather plants. They are said to be able to predict the weather for the season by the quantity of their flowers.
An immensely abundant bloom indicates a wet year, while a sparse bloom indicates a dry year. For the day’s forecast, look closely at the leaves of wood sorrel. When rain is imminent, it folds its leaves up or down. If folding is indicated, it will take a little while; if folding is evident, have your umbrella ready. In addition, water leaks out when the humidity increases. If you then touch the seed, it will fling around with a pressure of just over 17 bar.
Silver thistles (Carlina acaulis) are among the most reliable weather prophets, which is why they are also called weather thistles. If you observe the opening of their flowers, a few sunny hours are usually ahead. If they close, you can prepare for rain and you should slowly start bringing in your garden furniture cushions or covering them with a protective tarp.
Sunflowers (Helianthus) are rightly named because they show their flowers in full splendor only when the sun is shining. If clouds come closer, the flowers close relatively quickly. If the flowers remain closed despite the most beautiful sunshine, you can assume that a rain shower is coming soon.
Between March and October, you can use the cranesbill (Geranium) to predict the weather for the next few hours. During this time it blooms and has a seed stand. Pull out a seed. Press a small cavity in a piece of cardboard or Styrofoam and place it inside. The seed protrusion, also called a granule, will rotate clockwise as the humidity increases and counterclockwise as the humidity decreases.
Pine cones have been known as “plant meteorologists” for centuries. Firmly closed cone scales indicate impending rain. If, on the other hand, they stand far off or move into this position, the weather remains nice and dry. This works even when the cones are no longer hanging on the tree. Pine cones are particularly well suited, placed on the terrace as a hygrometer to indicate the humidity.
If it suddenly smells much stronger of woodruff (Galium odoratum) in your garden or on your balcony, this is usually due to the typical reaction to an increase in humidity and too expected rain clouds.