‘Weather garden’ displays effects of sun, heat, wind, rain

The moonflower attracts night-flying moths. During the day, the bud is closed tightly, left photo. It opens in the evening and is fully open at night, two center photos. The bloom lasts only one night and is spent by morning, right. Photos courtesy Stephen Vermette

by Stephen Vermette,

Department of Geography & Planning, SUNY Buffalo State

 

sundial in weather garden
While not as reliable as the clock on your phone, a sundial can help you keep track of time in your garden. Photo courtesy Stephen Vermette

Let me introduce you to something new – a weather garden.

A weather garden vividly demonstrates how sunlight, temperature, wind and rain affect plants in different ways. While these weather elements are a part of every garden, the key to a weather garden is displaying and learning about the specialized links between weather and plants. It does this through the choice of plants, as well as through fun and useful ornaments such as thermometers, wind vanes and rain gauges.

I planted a weather garden on a terrace at SUNY Buffalo State to illustrate the concepts of meteorology and climatology to my students.

My weather garden was in containers and was maintained for five years as part of the Department of Geography & Planning’s meteorology & climatology program. Each planting included a placard with a brief description paying homage to a noted weather element.

At the time, the campus was encouraging beautification, so it worked on that level, too.

Though it no longer exists, I delight in taking you on a virtual stroll through my weather garden. I hope that you may use these ideas in your own garden, providing you with a better appreciation of weather.

This week we will talk about sunlight. In future issues, we’ll talk about other aspects of a weather garden. See “Explore temperature in a ‘weather garden’” and “Weather garden: focus on wind, rain.

What additional plantings and ornaments would you consider for a weather garden? Please leave a comment below.

 

Sunlight

Ornaments

radiometer in weather garden
Sunshine makes the black and white sails inside a radiometer spin. It’s a fun feature in a weather garden. Photo courtesy Stephen Vermette

Two sunlight-related ornaments to consider in a weather garden are the sundial and radiometer.

The sundial is aligned so that the movement of the sun across the sky gives the time of day. The metal bar across the sundial face is called a “gnomon.” The shadow cast by the gnomon gives the time of day. The shadow rotates around the gnomon in a clockwise direction, and its position can be used to mark time. It has been claimed that the direction in which the hands on a clock rotate was chosen for this reason.

The radiometer is made up of black and white vanes or sails. Dark surfaces heat up more than white surfaces, so the dark vanes absorb more of the sun’s energy than the white ones. It is this difference in surface heat that causes the vanes to rotate. In other words, the rotation is powered by sunshine. Simple radiometers are curiosities that are affordable and readily available.

Plants

There are a number of plants that show a striking reaction to daylight—or to night.

Morning glory

As its name implies, the morning glory unravels its bloom in the early morning – blooming from dawn to late afternoon. Sometimes the bloom will not open on overcast days, as the plant prefers full solar exposure. When it does bloom, the blossom lasts only a single day. The most fitting variety (based on pigment) for a weather garden is ‘Heavenly Blue’, with its sky-blue color centered by a mock white/yellow sun. The morning glory’s link to the sun is historical too, as the Aztecs believed that morning glories were connected with the sun gods.

morning glory
The morning glory opens early in the morning and blooms until late afternoon. The variety ‘Heavenly Blue’ looks like the sun in the sky. Photo courtesy Stephen Vermette

Daylily

A similar pattern of diurnal or daily blooming is exhibited by daylilies. The daylily’s botanical name, Hemerocallis, means “beauty for a day.” The bloom lasts one day, then falls off.

Strawflower

Strawflowers open with the sun, and at night curl up into little balls. Why? The flowers produce fragrance to attract bees and other pollinators during the day, but at night, when there are no bees around, they close to conserve their fragrance. The blossoms appear dry (they contain less moisture than other flowers), a novelty tempting visitors to touch the blossoms. This dryness makes them ideal for creating dry bouquets.

Moss rose or portulaca

Similarly, the blooms of the moss rose (portulaca) open only during times of bright sunlight and don’t open on cloudy or rainy days. The moss rose is also called the time flower because the flower has a specific time to bloom. In Vietnam, it is called “hoa mười giờ” meaning “ten o’clock flower” because the flower is usually in full bloom by 10 a.m.

Gazania

Yet another example of blossom closing is the gazania bloom, which tends to close up on dull, cool days. The blooms open quickly once the clouds disperse and things warm up again – just think of it as nature’s way of making the flowers last longer.

Moonflower

The flip side can be found with the moonflower—the bud unfurls as the sun sets. The blossom is large, easily six inches across. Moonflowers unfurl in the evening so they can be pollinated by night-flying moths and, like most moth-pollinated flowers, the flower is white. And like the morning glory, the blossoms open only once, withering with the rising sun. The nightly show of blossoms offers a good excuse for an evening visit to the garden, as its moon-like shape and five-pointed star markings are a celebration of the clear night sky.

Photos courtesy Stephen Vermette
Strawflowers open with the sun and curl up at night to preserve their fragrance. Photo courtesy Stephen Vermette

Prayer plant

An interesting addition to the weather garden is the prayer plant. It’s an indoor plant that can be brought outdoors for the summer. These plants come from the tropics and live on the rainforest floor. The rainforest floor receives limited direct light, so these plants prefer indirect lighting. This plant was part of my weather garden because it has the unusual characteristic of folding and bending its leaves upright in the evening, as if in prayer.

Sunflowers

Sunflowers are an obvious choice for the weather garden. The sunflower possesses a large flowering head (made up of numerous flowers). Its name is derived from the flower’s shape and image, which is often used to depict the sun. A common misconception is that flowering sunflower heads track the sun across the sky.  Although immature flower buds exhibit this behavior, the mature flowering heads eventually stiffen and settle on a fixed easterly direction throughout the day.

Zinnia

Use of color association is an excuse to add the zinnia to the weather garden. The Aztecs originally gave the plant a name that means “hard on the eyes” because the flowers provide a rainbow of color.

Celosia

Celosia prefers exposure to full sun. The name is derived from the Greek for “burned” and refers to the flame-like flower heads. The yellow, red and orange plumed varieties especially bear a resemblance to the colors of sunrise and sunset.

Also see Our growing season is longer: What gardeners need to know about climate change in WNY, an article that talks about Stephen Vermette’s work that gives us more detail on how climate change is affecting various parts of Western New York.

 

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