Primroses (Primula polyanthus), an old-fashioned perennial popular in gardens for hundreds of years, is native to the Northern Hemisphere. Most primroses are hardy in U.S. Department of Agriculture plant hardiness zones 3 to 8. Over 400 species of the rosette-like plant grow both in the wild and cultivated in proper gardens, and one of the tricks gardeners learn early is that their primrose bed will last much longer if the plants are properly deadheaded.
Deadheading simply means grooming the plant. By removing the spent flowers, you prevent your plant from going to seed, and allow it to mature. Cutting back the spent flower stems also encourages new growth, so you'll see fresh flowers. Once your plants have started to thrive, a simple walk around the garden several times a week allows you to see how your primroses are progressing and whether you might need to clean up the flowers that are spent. Make sure you sterilize your scissors or pruning shears with rubbing alcohol before using them to deadhead your primroses.
- Start checking your garden in late spring.
- Carry a pair of scissors or a small pair of pruning shears in your pocket for the task. Some gardeners prefer to simply pinch away the spent flowers between thumb and forefinger, but sharp scissors make it easier to snip away the dead flower and leaves.
- Wear rubber gloves -- some people might be allergic to certain varieties of plants. It also curbs the spread of disease if your naturally oily fingers are protected. Certain floral diseases easily spread when fingers flit from one flower to another.
- Look for the flowers that have begun to fade or are drying out.
- Reach down to the base of the flower stalk and hold the dead flower gently.
- Bend the flower to expose the stem, and then either pinch or snip the dead flower away from the plant.
- It's wise to carry a small bag or wear an apron and drop the dead flowers into the bag or apron rather than on the ground. You can dump your deadheaded materials into a recycling pile when you're done with your task.
- Because too much water will rot primroses, check them occasionally and clip off any yellow or rotten lower leaves you see around the base of the plant. Removing rotten leaves promotes new growth. Your primrose bed might seem a bit droopy after you deadhead and trim old growth, but you'll be rewarded when new buds start to arrive.
- If primroses get too wet, they can develop conditions like crown or root rot and become susceptible to garden bugs, like aphids or spiders.
Once your plants stop blooming, pull the primroses from the ground or your pots, and put them into containers until fall. The best soil is gritty and humus-rich. Keep your containers in a sheltered spot, and keep the plants moist but not wet.
You can grow primroses from seed or purchase your plants from a grower. If you choose to grow them from seed, be aware that the seeds are exceptionally small and it is difficult for the novice gardener to be successful starting these plants from seed.
Most primula varieties flower reliably and are easy to grow. Plant them in sun or partial shade, and choose an area or pot that provides good drainage. Primroses don't like to be wet. If you can shelter them, you'll have very happy plants.
Offering your plants liquid fertilizer every two weeks or so will encourage them to produce fresh buds and create a beautifully flowering plant.
Most of the 450+ species of the genus primula like cooler weather and will not tolerate midsummer heat. They come in every color of the rainbow and the species names span the alphabet.
The varieties are distinguished by their rosette of leaves that resemble the leaves of a head of lettuce. In the center of the rosette are the flowers. Each flower has five petals joined at the base. Flowers appear on leafless stalks. Common colors include white, red, blue, yellow, purple and cream, but some species also produce bicolored flowers.