By John Green, Certified Texas Expert Gardener, Orange TX
The ‘Arctic Frost’ and ‘Orange Frost’ tangerine cultivars journey began in 1997 when Mr. Moy and Dr. Jerry Parsons collaborated, wanting to hybridize a winter hardy ‘Changsha’ tangerine. Their goal was to produce a Satsuma hybrid with enhanced cold hardiness, producing quality fruit with low seed count (image: plantanswers.com).
There is one significant detail that has not been lost to history, SETX gardeners love to grow citrus trees, despite everything! Orange, grapefruit, pomelo, yuzu, citron, tangelo, lime, lemon, tangerine, kumquat, and too many other citrus varieties to name. Mandarin orange varietals include tangerine varieties. The fruit is flat on the bottom (not round like orange varieties). Tangerines, especially Satsumas (in my opinion) are the sweetest, most tangy citrus and are most importantly…easy to peel!
Many gardeners (me included) enjoy cultivating fruit and citrus trees, but it has become much more challenging with climate change, shifting weather patterns that seem to be an exercise in futility! Many gardeners have lost numerous varieties of citrus trees which simply are not cold hardy past 25 to 30℉. Winter weather conditions, where temperatures remain extremely low for an extended period for many successive days and nights, always negatively impact citrus trees or they succumb to the elements.
Satsumas are the most cold-tolerant of sweet citrus. Texas A&M AgriLife Extension Services began field trials in 1994, to determine the most cold-tolerant citrus. Once the trails were completed, two satsuma varies performed well, ‘Miho’ and ‘Seto’, both were added to the Texas Superstar program in 2010. With continued testing, two other varieties were developed – ‘Orange Frost’ and ‘Arctic Frost’, both were added to the Texas Superstar program in 2014 and 2015, respectfully. Each produces quality fruit with few seeds, and both are extremely cold hardy.
Brief History:
In 1997, Mr. Ying Doon Moy and Dr. Jerry Parsons (Texas A&M Horticulture Extension Specialist) decided to hybridize winter hardy ‘Changsha’ tangerine with various Satsuma mandarins. The goal was to produce a Satsuma hybrid with enhanced cold hardiness as well as high quality fruit with a low seed count. Mr. Moy performed the tedious task of removing the ‘Changsha’ flower anthers, applying his collected Satsuma pollen, then extracting and nurturing the sexually produced embryo from the ‘Changsha’ seed. The successful seedlings were planted in containers to develop and mature for 6 to 8 years.
As a result of Mr. Moy’s work, we have new varieties of Satsuma x ‘Changsha’ tangerine hybrids which have enhanced cold tolerance, specifically:
- ‘Orange Frost™’ Hardy Satsuma- has improved cold hardiness having survived 12 degrees F. at Overton, TX. This variety was designated a Texas Superstar in 2014.
- ‘Arctic Frost™’ Hardy Satsuma- is the greatest cold hardiness variety having survived 9 degrees F. at Overton, TX. This variety was designated a Texas Superstar in 2015.
- ‘Bumper™’ Satsuma- has normal hardiness but chosen for its heavy fruit yield and holds Mr. Moy’s pride in this creation.
Satsuma hybrids (Arctic Frost & Citrus Frost) both require winter protection for the first three years until they are well established. They grow equally well if planted in the ground or in a large container. For the best winter protection, build a temporary frame using PVC pipe to “house” the tree, covering the PVC pipe with clear polyethylene. They require protection if temperatures are expected to fall to 25°F or below. Once established (after 3 years growth), winter protection is not necessary unless temperatures fall below 20°F. At the onset of cold weather, trees planted in the ground need to have a bank of mulch/ soil up and around the trunk of the tree. This will help protect the trunk if the main trunk dies back during severe cold weather. ‘Orange’ and ‘Arctic’ Frost satsumas are typically grown from cuttings or seeds and on their own root stock.
The tree can also be grown in a large pot, at minimum 24 inches wide by 24 inches tall or a large nursery pot (25 gallon). The tree must be repotted every few years since they will fill the containers quickly. Remove the tree from the pot, trimming the roots around the perimeter and bottom of the root ball. To remove old potting soil, use a blast of water from a garden hose. Repot using good quality soil in the bottom and around the sides, utilizing the same pot.
These cold hardy Satsumas are great for home garden plantings since they are produced from rooted cuttings. If the canopy is damaged by severe weather, all sprouts will recover to the original variety, so a minimal amount of winter protection is required. It is important to be able to move the container to a protected area for freeze protection when temperatures in the 20 degree F. range are predicted and back to full sun when temperatures are warm.
For trees in the ground, provide a nitrogen fertilizer each spring. If you notice a yellowing of the newer leaves (chlorosis) add iron following package directions. Container planted trees require a slow-release fertilizer, applied in spring before new growth appears. A supplemental water-soluble fertilizer can be applied every 2-3 weeks to support the tree and the fruit crop.
Until next time fellow gardeners, let’s go out and grow ourselves a greener and more sustainable world, one plant at a time! Please send your gardening questions to: jongreene57@gmail.com.
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