Plant the annual ageratum for its stunning purplish-blue blooms that appear all season long until frost.
Ageratum is a classic garden annual and one of thebest annuals for cutting.
It also offers a rare color in the flower world: blue, perfect for patriotic plantings.
Tom McWilliam.
Ageratum can also be found in several shades of pink, purple, and white.
No matter the color, these blooms are very popular with pollinators.
Butterflies enjoy visiting these plants and drinking their sweet nectar.
Credit: Bob Stefko
The plants begin to bloom in late spring and keep the show going until the first frost.
These rugged plants can withstand poor soil conditions and aren’t a favorite for deer.
However, ageratum should be planted in full sun in more northern locations.
How and When to Plant Ageratum
Plant ageratum after thelast frost date.
The young plants should be hardened off before planting them outside.
Space them 9 to 12 inches apart.
Credit: Marty Baldwin
Planting them too close together will lead to poor air circulation and can encourage the spread of disease.
Container plants require more frequent wateringdaily in hot summer weather.
Temperature and Humidity
Ageratums arewarm-season annuals; cold is their enemy.
Fertilizer
Their extended bloom makes ageratums heavy feeders.
Fertilize in-ground or potted plants with ageneral-purpose fertilizerabout once a month throughout the growing season.
Pruning
Ageratums are so floriferous and fast-growing that there is no need to deadhead spent blooms.
Credit: Doug Hetherington
The plant will quickly overgrow them, which is one of the reasons it is considered a low-maintenance annual.
Potting and Repotting Ageratum
With their compact size, the plants also make excellentcontainer plants.
Use a well-draining potting soil and feed them with a slow-release fertilizer.
Credit: Peter Krumhardt
Powdery mildew is most common during wet, humid weather.
Luckily, this won’t kill your plants; it is primarily unsightly.
‘Blue Danube’ Ageratum
Ageratum’Blue Danube' bears lavender-blue flowersand grows only 8 inches tall.
Credit: Illustration by Mavis Augustine Torke
‘Hawaii White’ Ageratum
Ageratum’Hawaii White' grows 6-8 inches tall and has white flowers.
Most salvias don’t like cool weather, so plant them outdoors after all danger of frost has passed.
French marigolds are frilly; some boast a distinctive “crested eye.”
Credit: Illustration by Mavis Augustine Torke
They do best in full sun with moist, well-drained soil and will flower all summer long.
They may reseed, returning year after year in spots where they’re happy.
Annual Vinca
You’vegotta love annual vincait really delivers.
Whether the summer is dry or wet, hot or cold, vinca plugs along unfazed.
Plant established seedlings in spring after all danger of frost has passed.
Vinca withstands drought but does best with moderate moisture.
This plant tends to be “self-cleaning” and needs little deadheading.
Yes, the plants reseed themselves freely from tiny seeds.
