Despite extreme hot temperatures in May, flowers in Danziger’s breeding facility retained their color and vibrancy

Last Tuesday and Wednesday, temperatures in Danziger’s main breeding nursery in Central Israel pushed 40 degrees Celsius (104 F) on two consecutive days, (43.2 (110 F) and 42.3 degrees (108 F) to be precise) marking the peak of what was an unusually scorching May.  Yet, visitors and staff were astonished to see a flourishing display in the company’s outdoor nursery.

“When it comes to understanding how well a variety can tolerate extreme heat and dryness, there’s no substitute for seeing what actually happens during a really hot spell. That’s exactly what we got the chance to witness last week and the results were very satisfying. In particular, it gave us the opportunity to observe how the heat tolerance in the varieties we are developing managed the high temperatures in a real-life and real-time situation,” said Amir Zuker, R&D Director responsible for perennials, annuals and cut flower breeding and research at Danziger.

3 biggest surprises from this hot spell

During a period of warm and hot weather, no one would be surprised to see Petunias, Portulaca and Phlox thriving. However, the same cannot be said for Bacopa, Nemesia and Diascia, varieties normally associated with cool or mild temperatures. But, that’s exactly what happened this week. Here’s what we discovered:

Bacopa is usually very sensitive to high temperatures and dry weather. Despite the heat wave, the Bacopa continued to flower, maintaining flower abundance and good leaf quality. There were no signs of a cessation of flowering, loss of leaf firmness nor yellowing.

Nemesia, which typically starts to suffer in the heat, showed virtually no signs of stress.  One might have expected the Nemesia to cease flowering during this period, but again, counter to expectation, they continued blooming beautifully.

New varieties belonging to our new Diascia,  trinity series, withstood 3 weeks of sustained hot weather, and temperature extremes of over 40 degrees. One might have expected the Diascia to have lost the flowers, leaf damage or even died completely. But, judging by the florescence we witnessed in the garden, the new trinity Diascia demonstrated amazing heat tolerance.

3 key take-outs for the value chain

With climate change, Danziger is investing considerable research efforts in breeding crops with better heat resistance. The recent heat wave, allowed Danziger to get a sneak preview of the success of our recent work. Here are several observations:

Breeders: A very strong indication that these 3 varieties – Bacopa, Nemesia and Diascia – could have excellent garden performance in hot weather.  We anticipate that breeders will now be encouraged to use hot temperatures to breed and positively select good plants with good garden performance that can withstand severe heat and very dry weather.

Retailers: A good indication that these new varieties have heat tolerance and extended shelf-life so essential to garden centres and other points of sale.

Gardeners: A good chance for gardeners to start enjoying Bacopa, Nemesia and Diascia as summer varieties, with added confidence these can prolong the season, and do very well in low humidity and very hot high temperatures.

What we learned at Danziger

“In general, we test our bedding plants in the regions in which these products are marketed and sold, for example the US, North and Southern hemisphere, and different regions in Europe and other locations all over the globe. Israel – with its hot climate – is the perfect testing ground to expose plants to very high temperatures, so we gain valuable data from how our plants perform in Israel’s extreme heat and low humidity. We have been working in increasing the ability of our bedding plants to withstand extreme heat, but we are pleasantly surprised just how well they have performed in terms of their flower abundance, leaf quality and the vividness of the colors – even in 42 degree temperature,” added Amir Zuker, R&D Director at Danziger.

The different varieties of annuals were planted in large pots, and have been transplanted in the garden under full sun in Danziger’s nursery since the beginning of March.  Danziger welcomes visitors to its nursery to see with their own eyes how well these varieties are performing in the heat. And summer is still a few months away…what will we discover then.  Watch this space.