By: Sandie Wick, sandie1000[at]aol[dot]com, Consulting Rosarian, Jupiter, FL
With the advent of Fortuniana rootstock, growing roses in South Florida has become not only manageable, but an extremely rewarding pastime. When all others are sitting with a catalog and dreaming of next spring’s first bloom, we are in the most glorious flush of bloom, cutting buckets of roses for our Christmas Dinner tables. Prior to using Fortuniana as a rootstock, it was so difficult and the mortality rate was so high due to the sandy, nematode infested soils that many people just gave up and let their plants die and declared “you can’t grow roses in South Florida.” Well, thank goodness some people persevered because today we can grow roses 365 days a year, and here’s how and why.
Yes, you can grow great roses in Florida, but that wasn’t always the case. One of the most important ingredients in a South Florida garden is rootstock. Fortuniana rootstock, the only rootstock of choice for South Florida gardens, also known as Double Cherokee, was discovered in Ninghpo, China by Robert Fortune around 1848, and sent by him to the Royal Horticultural Society in London. With its superior root system and the general hardiness of the plant, Fortune felt certain that it would thrive in every English garden. Unfortunately, it could not endure the harsh English winters.
During the 18th and 19th centuries there was a great exchange of plant material and horticultural knowledge between countries. It seems quite likely that Rosa fortuniana was sent to America sometime in the early 1900′s. The earliest mention of it use as a rootstock was in 1903 in Australia. A rose grower near Perth was short of stock and decided to bud some plants onto Fortuniana stock; the vigor and floriferousness of Fortuniana became apparent, and continues in Australia and New Zealand even today. The popularity of Fortuniana grew like wildfire.
Mrs. B.F. Lampkin of Sarasota, Florida was instrumental in introducing R. fortuniana to Florida. She collaborated with Dr. Samuel McFadden, an ornamental horticulturist from the University of Florida at Gainesville, where he tested Fortuniana rootstock extensively and developed a mist system for rooting cuttings that increased the success rate from 30% to 80-100%. Dr. McFadden also discovered that Rosa fortuniana passed on great vigor to even weak varieties, transforming them into stronger bushes with flowers of striking quality. The rootstock was very heat tolerant, but sensitive to the cold.
Unlike our native plants, many roses, particularly hybrids, do not do well on their own roots. Their natural roots are prone to just about every disease and insect known to man. Therefore, they must be grafted or budded onto hardy rootstock with an extensive root system. Without a good root system, a plant cannot absorb the nutrients it needs to flourish.
The long, fine root system of Fortuniana is an ideal rootstock for sandy soils. The extensive fine roots enable the plant to absorb the nutrients and water it needs to produce food for growth. The more vigorous a root system, the more food it can transfer to the plant. The more food it can transfer to the plant, the faster it grows. Hence, the rose grows faster and the size of the flowers are also greatly increased.
As an added bonus, the roots of Fortuniana are very resistant to the many varieties of nematodes found in our sandy soils.
Fortuniana is not only more resistant to nematodes, but also to gall, stem die-back, and root diseases such as Pythium, Phytophtora and Rhyzoctonia. No other rootstock in all the world can compare with the qualities found in Rosa fortuniana. It will also live and produce decades longer than any other rootstock. Reportedly, there are some roses planted in Central Florida more than 40 years ago that are still surviving and are the size of trees. The fact is, Dr. Malcolm Manners from Florida Southern University does not even recommend a second choice in comparison to Fortuniana.
So, don’t waste your time or money attempting to grow roses on any rootstock other than Fortuniana; they have a maximum life span in Florida of two years before they begin to decline and eventually die.
Fortuniana rootstock does well in almost any type of soil with the possible exception of heavy clay, and will even survive some freezing temperatures if allowed to acclimate. Rosarians all over the South are now growing roses on Fortuniana rootstock and loving it.
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