Frostkiss Hellebore Production 101

April Herring-Murray

As the first plants to bloom in spring, hellebores demand attention and will earn a special place in your perennial assortment. There are many different types of hellebore on the market today, so it’s important to be knowledgeable with these varieties before beginning a program to be sure you get the results you expect. 

Three main categories of hellebore are sold in the U.S., these include niger spp., orientalis spp. and hybrids. Frostkiss Hellebore fall in the hybrid category; these are easy to grow when just a few key growing tips are followed. Unlike many orientalis spp. on the market, which can take two years to bloom, the Frostkiss series will bloom within one year from the time of planting and crops are very uniform from the point of overall appearance and bloom time. 

Although the Frostkiss series are early blooming perennials, they’re late blooming for hellebore. These are not timed for Christmas like the niger types, but are timed for early spring (February to April depending on climate), so they’ll fit right in with other early season perennial products.

Quick tips for growing Frostkiss Hellebore
• Hellebore liners can be planted in two seasons—spring and fall when they’re actively growing. 
• Hellebores are dormant in the summer months; therefore, it’s not recommended to pot liners during this time.
• Plants should be shaded at 30% in the summer months to prevent overheating and/or burning of foliage.
• Hellebore doesn’t like to be watered in the hottest time of day, so water them early morning or late evening.
• Hellebore need a very well-drained, coarse soil with lots of aeration; pH should be at 5.5. A peat-based soil with decomposed bark works best.
• Opposite of many plants, hellebore needs more fertilizer in the fall to help initiate flowers.
• Keep a hellebore actively growing; if they stop growing because of low fertilizer, it can set back the growth by two to three months.
• Flower initiation occurs with shortening of days in the fall and lowering of temperatures, at around 40 to 50F (4 to 10C). 
• Keep frost-free during the winter in a cold greenhouse, 32 to 45F (0 to 7C), to prevent flower delay.  

Transplanting and finishing
Whether crops are spring or fall planted, it’s advisable to pot as early as possible in the season to get the growth needed to fill the pot. This is particularly true in the spring, as hellebore only actively grow when the temperatures are cooler, so delaying planting can stunt the overall finish size of the crop and decrease the flower bud count. 

The chart below gives recommended planting dates and corresponding crop times. For growers not wanting such a long crop time or for growers wanting to avoid over-summering a hellebore, fall planting is highly recommended, as it can cut the crop time in half.

Fertilization
Hellebore need a steady feed throughout the growing cycle with an EC of 1.2 to 1.5. A slow release eight- to nine-month fertilizer is recommended when spring planted. In the fall, hellebore start initiating flowers, so they need extra nitrogen (N) and iron (FE) during this time. This can be supplied using a liquid drench.

Spacing
For most of the crop life, hellebore should be kept can-tight. This seems like the wrong thing to do, as growers have been trained to space crops as soon as the foliage starts to touch. Hellebores enjoy cool roots, so keeping plants close together causes the foliage to shade the pot and prevent root burn. Unlike many other plants, hellebores won’t stretch when grown can-tight. Once plants start to flower in the spring, they can be spaced to give flowers room to develop.

Pinching
Never pinch a hellebore; every leaf of the hellebore is helping to form flower buds of the future, so removing leaves will decrease flower count and overall finished quality. Only remove damaged leaves at time of shipping finished product.

Diseases & pests
Hellebores are tough plants and rarely get diseases. The main disease issue seen is Botrytis in the flowers.  Prevent this by keeping plants dry and in an area with good air flow. Watch for aphids and spider mites. GT

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For more detailed growing information, contact April Herring-Murray, New Product Development and Marketing Manager for Pacific Plug & Liner, at (831) 768-6319 or aprilh@ppandl.net.