Zones 4 thru 6: These are the colder zones in the United States. The winters in these zones can be snow covered and very cold for extended periods of time.
Zones 7 thru 9: These are temperate zones that do not get overly cold in the winter months. They can get sub freezing temperatures, but usually not for extended periods.
Zones 10 thru 12: These regions have very mild winters. They can get sub freezing temperatures. These weather events are short-lived and rare through the winter.
Zones 1 thru 3: We have no current hardiness or flower response data in these climate zones.
One of the greatest features of Heuger’s breeding efforts is that our Helleborus can provide fresh new flowers from November through March. One of the greatest challenges when we market this product is getting our consumer (gardener) to understand how to enjoy this feature. It is quite possible that the lovely flower of our Helleborus has caught your eye in the garden center or in the flower shop and made you purchase the plant in the winter months. North America has many climates and this might confuse you. We hope that this page helps you understand the flowering response of the two series.
The first thing to understand is that our breeding offers two classes of Helleborus. The Helleborus Gold Collection® is a group of interspecific hybrids we have developed through breeding. Our Spring Promise® Garden Hybrids is another class of Helleborus x hybridus, also from Heuger breeding. Each class has genetics characteristics that cause flower response in the garden to vary.
We are trialing our two series of Helleborus in many locations across North America to accurately measure hardiness and flowering response. We have new varieties entering the market each year. Please be aware that to make definitive statements on hardiness and flower response takes years of trialing. The information we are presenting is based on trials to date and may be subject to change as we gather more information.
The American Horticulture Society produces a ‘Plant Heat Zone Map.’ This map tries to define general temperature zones in the United States. Locate where you live on this map above. We have broken down the map into three categories:
The varieties in the Helleborus Gold Collection® flower early in the ‘winter to spring’ gardening season of Helleborus. For gardeners planting in ‘Zones 4-6’ the earliest flowering varieties are HGC Joshua® and HGC Jacob®. Closely following these varieties into flower is HGC Josef Lemper®. The gardener who lives in ‘Zone 6’ can sometimes enjoy these three varieties in your garden in November. For those living in ‘Zones 4-5’ your fall weather may be too cold and snowy for these two varieties to show their faces. All is not lost because they will sit patiently waiting for spring weather to allow them to spring into flower.
HGC Cinnamon Snow®, and HGC Silvermoon® are the next two varieties to show their faces in the garden. In the milder winters of ‘Zone 6’ you may catch an occasional glimpse of the varieties in January or February. It will be rare to see these two varieties in ‘Zones 4-5’ in these months. Their flowers will continue to develop under the snow. A good reference point for flowering will be Snow Crocus. As your Crocus show their flowers in the garden your Helleborus are not very far behind.
HGC Pink Frost® and HGC Green Corsican® are the latest responding varieties of the Helleborus Gold Collection®. At the end of a mild winter in ‘Zone 6’ these varieties could begin to flower in later February into March and April. Gardeners in ‘Zones 4-5’ will again need to wait for spring to ease into place before seeing color.
Spring Promise® Garden Hybrids traditionally flower late February into March in ‘Zones 4-6’. They show their colors later than the HGC®. They may coincide with HGC Pink Frost® and HGC Green Corsican® in garden response.
More than likely, a few gardeners will get a sneak-peak at the earliest flowering HGC varieties in early November in ‘Zones 4-6’, but the majority of flowering will occur on most of the varieties as your earliest bulb plants begin to show in the garden. One of the nice features of our Helleborus is that unlike bulbs, they do not need replanted each season.
For those of you who garden in these regions the Helleborus Gold Collection®
and Spring Promise® Garden Hybrids
should provide you the full glory of our breeding efforts in their natural seasons. The climates that are present in these zones work ideally with our genetics. As a result, we can outline a sequential flowering schedule by month that should be somewhat reliable. Again a reminder – these responses can fluctuate based on weather patterns in any given year. See below.Helleborus Gold Collection®:
‘HGC Joshua’: November
‘HGC Jacob’: November
‘HGC Josef Lemper’: December
‘HGC Cinnamon Snow’: January
‘HGC Silvermoon’: January
‘HGC Green Corsican’: February
‘HGC Pink Frost’: February – March
‘Spring Promise’: February – March
These are the warmest areas of North America. The plants will respond differently in the warmer areas than they do in the colder regions. When the weather is severely cold the Hellebore will tend to sit patiently until spring emerges. When the weather is too warm it delays the flowering. In these heat zones some colder weather usually arrives in the shortest days of winter and allows the flowers to be established in the plants. As a result, flowering will be pushed back. We have not done extensive trialing in these warm climates so it is difficult to make accurate predictions as to if and when flowering will occur.
Download the North American Response Map in PDF format here!