Bountiful blooms

Abundant rainfall helps endangered Gilboa iris spring back

After drastic decline 15 years ago, count of iconic flower shows significant increase

Sue Surkes is The Times of Israel's environment reporter

An endangered Gilboa iris blooms on Mount Barkan, northern Israel, in March 2024. (Times of Israel)
An endangered Gilboa iris blooms on Mount Barkan, northern Israel, in March 2024. (Times of Israel)

Generous winter rainfall sparked a particularly bountiful year for the endangered Gilboa iris, which has just ended its flowering season on Mount Barkan in the Gilboa range in northern Israel, according to the Israel Nature and Parks Authority.

This year, there were 550 clumps of flowers and nearly 2,500 flowering stems, compared with just over 300 (1,150 stems) in 2023 and a little over 100 (around 300 stems) in 2022.

A count in March has been going on since the 2008-2009 winter season, which saw a rapid decline of this iris in the northwestern area of the Gilboa range.

The parks authority assumes that this was because of dry winters and rocky conditions that limit the soil’s ability to retain water.

Figures from the Israel Meteorological Service show that 579 millimeters (22.8 inches) of rain fell on the Gilboa up until Monday — which is 151 percent of normal rainfall by April 8, and 144% of the average for the full season.

An endangered Gilboa iris blooms on Mount Barkan, northern Israel, in March 2024. (Times of Israel)

The Gilboa iris grows only in Israel and is one of around 10 so-called “royal irises” (botanists have yet to agree) that flower in different colors and conditions, from the north to the south of the country.

Botanically, royal irises are known as members of the Oncocylus section of irises. Onco means mass, or bulk in Greek, and cyclus means circle. The name refers to the ball-like shape of the flower.

In Hebrew, the group is known by the lyrical name heichal, meaning a palace, temple, hall or inner sanctum. Indeed, the upper petals fold over one another to form a kind of chamber.

More than 18 years ago, botanist Dr. Yuval Sapir of Tel Aviv University, who runs the university botanic garden and is an expert in Oncocyclus irises, set out to establish why nighttime solitary bees visited Oncocyclus irises at dusk and spent the night inside them, even though these irises do not offer any nectar as an enticement.

His research, carried out together with botanists Avi Shmida and Gidi Ne’eman, concluded that the dark spots on the flowers of these irises absorb heat during the day and release warmth until the following morning, allowing bees to warm up at night and get a head start on competitor bees that sleep on the ground. It’s a win-win, as the bees get covered in pollen during the night, which they take to their next irises, aiding fertilization.

Lortet’s iris. (Zachi Evenor – Flickr/CC BY 2.0 Wikimedia Commons)

While the wild Gilboa iris season is reaching its end, flower lovers can still catch another royal iris — Lortet’s iris — in northern Israel on Tel Hazor. According to Facebook, other recent sightings have been opposite the entrance to Tel Regev and at Kibbutz Ayelet Hashahar.

Following several years of good rainfall, the parks authority confirms that this iris is also on an upward trend.

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