Annual phlox, or Phlox drummondii, is a species of plant from the Polemoniaceae family that has flown under the radar for many years. It’s not a new species by any means, having been cultivated in gardens since the early 1800’s, but it didn’t gain widespread popularity in the cut flower industry until more recently. Annual phlox have delicate stems that don’t ship well, making them a cut flower that can only be grown and enjoyed locally – they have also been bred to represent a vast array of color palettes including soft muted pastels including ‘Cherry Caramel’, ‘Crème Brulé’, ‘Blushing Bride’ and ‘Phlox of Sheep’ which are all popular among small scale flower growers in the USA. These plants are often considered tricky to start from seed due to some specific requirements during germination, so we are happy to do the most challenging part for home gardeners and offer well-started plugs as an alternative to seeds. Due to seed shortages we won’t have all of the above varieties listed at the same time, but we will have one or two of them available on our catalog for spring shipping. These plants should be considered tender annuals – they are fast growing and prefer warmer weather, so there is no reason to plant them before the time of your last frost in the spring. They can be grown in the spring and summer months across all the US unless you live in the extreme south, where they might be better grown over the cooler but frost-free winter months. They are quite adaptable and can tolerate a wide range of conditions, so they should work in most gardens.

Order Phlox paniculata plugs to be delivered around the time of your last frost – they can be planted when the soil is on the cooler side in early spring but should not be exposed to hard frosts as new growth is tender. When the plugs arrive, harden them off to outdoor elements and plant them out soon after arrival to prevent the plugs from becoming rootbound or stressed in the plug trays. Prepare the growing site before planting by breaking up the soil and incorporating some compost and balanced granular fertilizer; phlox paniculata can tolerate most garden soils but prefer loose, well-draining, loamy soil that has good water retention and medium fertility. These plants will perform the best if planted in full sun – shady conditions will cause week, floppy growth and fewer flowers.

Space plugs about 12-24 inches apart for a large singular clump of phlox once the plants reach maturity – in a garden setting you can also space them out more generously but know the plants won’t reach their full size for 3 or so years. The tighter spacing is recommended for more intensive cut flower production, but tight spacing also promotes lack of airflow and fungal issues, so the more space you can provide, the more airflow there will be around the plants and the healthier they will be. Pinching the plugs is not necessary as the plants will naturally send up more stems as they mature; don’t expect a big show in the first and second year after planting – the first thing newly planted plugs will do is work on a hearty root system to support more vegetative growth in coming years. You will see some flowers, but your patience will be rewarded with large clumps of flowers after the plants have a couple years to establish and size-up. When the flowers fade, cut the entire plant back to within a few inches from the ground and it will send up a second flush of blooms. These plants can grow quite tall – up to 3 or 4 feet when mature, but the stems are stiff and durable, and the plants can support large clusters of blooms without need for staking or additional support. Perennial phlox are notorious for succumbing to powdery mildew later in the summer, but the newer cultivars we are offering through Garden Club have resistance to powdery mildew bred into them. To avoid infection, try to keep the foliage dry when watering – prolonged periods of wet foliage can encourage fungal growth.

If you bring some phlox stems inside to enjoy in a vase, cut the stems when a couple individual florets are open and the rest are still in bud. These buds will continue to open in the vase, prolonging the vase life. Cut early in the morning or later in the evening when the sun is less intense, as the plants will be more hydrated at this time and the cut stems will be less likely to wilt in the vase. Use fresh, clean water, and change the water frequently to keep the flowers looking fresh longer; the use of a floral food may help but is not absolutely necessary. Annual phlox don’t have the longest vase life which tops out at about a week, but the cheerful little flowers add a lot of character and whimsy to an arrangement in a palette not seen in many other varieties, making them a valuable addition to home gardens across the country.