Past Articles Library | Growing Evening Primrose
Believe it or not, the Evening Primrose belongs to the Oenothera genus that contains 145 herbaceous plant species. These can be annuals, biennials, and perennials but most gardeners only grow them as annuals. Common names for the Oenothera include Evening Primrose, Desert Evening Primrose, White Buttercups, and Sundrops with the latter name describing the yellow, cup-shaped flowers. But the flower color is not limited to yellow. They can also be pink, orange or white.
If you plan on growing Evening Primrose as a perennial, keep in mind that it will do fine in USDA Plant Hardiness Zones 3 through 11. This plant can survive in areas of partial shade but really showcase their blooms when planted in full sun. Depending on the species, the height can range from 6 inches to 3 feet and a spread of 8 to 24 inches.
When it comes to the blooming season, you will need to check out the species you have selected. Most Evening Primroses will bloom from spring to fall.
Evening Primrose can be propagated through seeds and division. When it comes to seeds, the planting can occur indoors or they can be directly seeded into the garden space.
Planting the seeds indoors will give you a jump on the gardening season but this will need to occur 10 weeks prior to your local frost free date. If you do not know your local frost free date, contact your local extension agent for this information.
Once you have that date, mark your calendar and prepare for that date. Preparation means getting your containers in order. In this case, while you could use a flat or plastic pot, the best approach is to use peat pots. Using this type of container will allow the plants to remain in the same pot until you get them planted in the garden space.
To begin this planting process, first fill the peat pots with soil and place in tray. After all the peat pots have been filled and placed in the tray, fill the tray with water. The water will be taken up by the peat pots and will moisten the soil. Continue to add water to the try until water remains in the tray.
If you are a frugal gardener, you will want to plant one seed per pot. There is no need to dig a hole, these seeds can simply be placed on the soil’s surface and then covered with 1/8 inch of soil. If you are not a frugal gardener then simply sprinkle the seeds on the soil surface and sprinkle with soil. After all the seeds have been planted, mist the soil’s surface with water.
Place the planted peat pots in a warm room. You may have noticed at this point that I did not mention sunlight. These seeds will germinate in the dark and their arrival should appear as green dots in 9 to 12 days. Once the green dots appear, move the planted containers to a sunny window.
Continue to monitor the planting medium’s moisture and water when needed. A week prior to your local frost free date, you will need to harden off the seedlings. This process is easy and only requires you to slowly move the plants outside so that they can get used to their new home. Do not plant your Evening Primrose in the garden until the plants have spent 24 hours outside.
Once you are ready to plant your Evening Primrose seedlings in your flower garden, there are a few things you need to know. First, Evening Primroses like a light soil that is well draining along with a soil pH of 5.5 to 7.
After you have found the ideal garden space for your Evening Primrose, the next step is to plant your seedlings. They will need to be space 8 inches apart. Prior to digging the holes, go through the garden space and mark the planting locations with powdered milk.
Now that you have your planting areas marked, dig the holes so that they are as deep as the container the seedling is in. In this example, we used peat pots. While in normal situations, you would remove the plant from the container this is not so when it comes to peat pots. Place the pot and plant in the hole to check the depth. If the depth is correct, slightly bend down the top of the pot. The reason for this step is simple. If this lip ever comes above the soil level it will act as a wick. To prevent this, simple bend down the lip and fill in with soil. Water in the seedlings after all plants have been planted.
Since this plant can reach the height of 3 feet, you may want to add a plant support at this stage. It is easier to do this step now then when the plants have reached the height when they need support.
If you do not want to get a jump on the gardening season, simply prepare the garden space by removing any unwanted plant material and loosen the soil. Directly sprinkle the seeds on the soil surface and cover with 1/8 inch of soil. Water the seeds in and keep the soil evenly moist.
As far as the remaining care goes, if you are just growing Evening Primrose as annual, do not worry with fertilization. On the other hand, if you are growing them as a biennial or perennial you will want to feed them in the spring with a layer of seasoned cow manure.
Since Evening Primrose is considered an invasive species, you will want to keep them from going to seed. The easiest way to do this is to just remove the spent blooms. This simple task will keep your plants looking their best and prevent Evening Primrose from appearing in other spaces beyond the intended area.
If you do find escaped Evening Primrose, just dig them up and share your plant wealth with your gardening friends.
To enhance the beauty of this plant, consider interplanting Evening Primrose with daylilies. Doing this will provide constant color throughout your gardening season.