How to Plant Holly Seeds
Growing holly (Ilex spp.) from seed is a time-consuming process, and it can take years before a new green shoot will even appear. Seed pretreatment can shorten germination time, but planting this seed still requires patience and perseverance. Evergreen holly trees and shrubs provide winter interest with bright red berries. Hardiness varies by individual species among U.S. Department of Agriculture plant hardiness zones 5 through 9b.
Seed Dormancy and Pretreatment
Holly seeds have a long dormancy period that is tough to break, and they can take up to three years to germinate. Pretreating holly seeds can decrease the time from planting to germination, but germination rates still vary. To pretreat holly seeds, pack them in peat moss and store them at 68 to 86 degrees Fahrenheit for one to two months.Then move them to a spot that is 41 degrees F for two to three months.
Holly seeds require one to two months of warm conditions, followed by the two to three months of cold temperatures to break dormancy. By direct seeding outdoors in fall, you can take advantage of the natural warm fall temperatures followed by the winter chill. In spring, the soil starting to warm up again will stimulate germination. Though this cuts down on planting and transplanting, holly germination can still take one to three years.
Planting Holly Seeds
You should plant holly seeds 1/4 to 1/2 inch deep. Space the seeds 3 to 6 inches apart to save space during the lengthy germination period. Once the seedlings are large enough to handle, you can transplant them into individual pots. Keep the soil moist by watering whenever it feels dry to the touch. Use seed flats and a sterile seed-starting mix if you choose to plant holly seeds indoors.
Some holly varieties that gardeners favor include American holly (Ilex opaca), native to the northwestern United States. This species grows up to 30 feet tall and is hardy in USDA hardiness zones 5 through 9. Another North American native, Yaupon holly (Ilex vomitoria) grows 10 feet tall and is hardy in USDA zones 7a through 9b. Savannah holly (Ilex x attenuata) is hardy in USDA zones 6a through 9b and can be grown as a landscape tree or pruned into a hedge.
- University of Texas at Austin Native Plant Database: Ilex Opaca
- University of Texas at Austin: Ask Mr. Smarty Plants
- North Carolina State University: Overcoming Seed Dormancy
- University of Illinois Extension: Holly Plant
- Missouri Botanical Garden: Ilex Opaca
Eulalia Palomo has been a professional writer since 2009. Prior to taking up writing full time she has worked as a landscape artist and organic gardener. Palomo holds a Bachelor of Arts in liberal studies from Boston University. She travels widely and has spent over six years living abroad.
How to Plant Holly Seeds. Growing holly (Ilex spp.) from seed is a time-consuming process, and it can take years before a new green shoot will even appear. Seed pretreatment can shorten germination time, but planting this seed still requires patience and perseverance. Evergreen holly trees and shrubs provide winter …
How to grow Holly
Scientific Name: Ilex aquifolium
Scientific Family: Aquifoliaceae
Holly berries ripen in the late autumn, usually in November or December. They sometimes remain on the tree throughout the winter, so could possibly be collected as late as April the following year. Berries are stripped from the trees by hand.
Collecting holly berries
Extraction and storage
The collected berries should be separated from any twigs and ‘de-bunched’. They can be left in buckets or baskets for a week or two, provided they are stored in a cool, dry place. Click here to see the simplest way to extract the seed from the fleshy fruit. Ideally the extracted seed should be pre-treated immediately.
Extracting holly seeds
Mix the seeds with equal parts horticultural sand or a sand/compost mixture. Use 50% leafmould or peat-free compost and 50% horticultural sand. For each handful of seeds add two or three handfuls of mixture. Select a pot that has enough room for this seed/sand mixture (and a bit more) and put a layer of stones in the bottom. Cover the stones with sand. Place the seed/sand mixture on top of this and cover this with 2-3cm sand. Label the pot and stand in a shady spot outdoors.
The pot needs to remain outside for eighteen months. This is where patience is required! Water the pots if they show signs of drying out and protect from birds and mice if they discover your seeds. We will be sowing the seeds the second spring following collection. Holly seed has a very hard outer seedcoat that needs a full summer (warm temperatures) to break down, allowing oxygen and water to reach the embryo tree inside.
After the seeds have spent a whole summer and the following winter outside, they are ready to be sown (eg. collect December 2017 and sow spring 2019).
Holly doesn’t like its root to be disturbed once it is growing. For this reason it is best grown in a pot – about 8cm in diameter. Sow each seed as it begins to germinate (when you can see a small root emerging). Sow one per pot. Cover the seed with a little compost and firm gently.
Because holly is grown in pots, it will be more susceptible to drying out. Ensure that the pots are kept well watered and fed.
During the first year in pots, your holly seedlings will grow up to 20cm in height. In the autumn of this first year (about September/October) transplant the young trees into 1- or 2-litre pots, taking care not to disturb the roots too much.
If kept well fed, they will reach a size large enough for planting out during the second year.
Prepare the site well by clearing away any weeds or grass and make a hole big enough to accommodate the root ball. Carefully ease the plant out of the pot (tapping gently if needed) and place carefully in the hole. Make sure the stem it at the same depth as it was in the pot, and firm back the soil.
Holly trees can be easily grown from seed collected during the winter. Pick ripe, red berries and follow these instructions. A bit of patience is needed!