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How to Grow Ageratum Flowers

What is an Ageratum?

Ageratum is a flower sometimes easier to show than describe because the second you look at it, if you've ever seen it before but not remembered its name, you instantly recognize it from its unique look and flowers.

Mostly it is known and loved by gardeners and landscapers because of its blue flowers; although there are a number of other colors, including pink, lilac, lavender and white.

The majority of ageratum plants are from 6" to 10" tall and wide, having the look of a mound to them. There are newer varieties that are taller, but the shorter, compact variety are by far the most well known and popular among them.

Since they are so low to the ground and compact, they're great for placing in strategic places in your yard or garden, as well as grouping them together if you like that look.

They are among the most versatile of plants, also looking great in containers.


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How to Propagate Ageratum

There are a couple of ways gardeners propagate ageratum. The first is by sowing them directly in the ground once the danger of frost is gone.

While this works, it will take more seeds and work, as you'll have to plant more in the areas your sowing to make up for some that won't sprout, as well as having to pull out the weaker of those that emerge in the same seed cluster you planted, as they don't do as well if overly crowded.

Sowing Seeds in Pots

The best way to propagate ageratum is to sow the seed in pots about 6 to 8 weeks before the last frost date in your region.

Place at least a couple of seeds in each small pot in order to produce the number you want in case there is some germination failure. And like ageratum planted in the soil, you want to keep the most healthy of the plants emerging while removing the others and throwing them away.

Just lightly press the seed into the mix. Ageratum need light to germinate, so if you have problems with them being held in place, an alternative would be to sprinkle a tiny bit of sand or other substance on the seeds for that purpose. Otherwise just press them in the mix and leave them partially showing. Best practices is to press them into the mix and let them lie there.

Sowing Seed in Flats or Trays

If you're sowing a lot of ageratum seeds, you'll face the problem of working with very tiny seeds.

To allow for a more uniform seeding without the seeds being all clumped together, take an old, clean salt or pepper shaker (with small holes) and place the seeds in them and lightly shake them onto the tray or flat.

This gives you a lot better control and results than attempting to pinch seeds and release them.

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Watering Seeds

This should lead to the question of watering the seeds because of the fact if you over water the loose seeds will just go down the sides of the container, or possibly even rot.

To battle that, just spritz a light coating of warm water using a spray bottle over the seeds. That should easily give them enough water while keeping the seeds where you want them.

Using Warming Mat

If you have a warming mat you can use to aid your ageratum starter pots, place it close to a window with direct sunlight, setting it at 75 degrees Fahrenheit for the day hours, lowering it to 58 degrees Fahrenheit during the night.

They don't take long to germinate, with the norm being from about 5 days to a week and a half.

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Transplanting Ageratum

Ageratum don't take a frost so wait until the last frost date is gone before planting your seedlings in the soil.

If you're planting a shorter variety, space your plants from six to nine inches apart. With the taller varieties, increase your spacing to about twelve inches apart.

In most zones full sun is the best for ageratum, but if you live in a very hot climate, allow for some light shade to compensate for the extra heat.

For cooler zones, full sun is almost a must for them, with a little shade if unavoidable where you are planting.


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Insects and Diseases

Ageratum is highly resistant to diseases and insects, although there are occasional exceptions to that rule.

In the case of insects, sometimes there can be a problem with mites. Most of the time they are easily treated with an insecticide such as Sevin or insecticidal soaps.

As for diseases, they are very rare. But more than likely if there is one that appears, it'll usually be effectively treated with a fungicide.

Overall they plant is very resilient and relatively labor free in that regard.

Ageratum Care

Other than unusual circumstances, the only real care ageratums need during the season is for aesthetic reasons, and that is to deadhead them to keep up the appearance of the flower and garden.

Besides that, there is little to do unless you need to pull out some weeds out once in a while to clear the area for better growth and looks.

Harvesting and Storing Seeds

If you want to harvest ageratum seeds, it's really very simple. Just allow the seed heads to dry out and the remove them from the plant and collect and store the seeds.

Keep in mind that these seeds are unlikely to be exactly true to the plant you took them off of.

Store them in a dry, cool place and begin the process over next year at the right time.

Prolific Ageratum

The prolific flower can drop a lot of seeds and create an effect you weren't expecting. To manage this you'll have to do some deadheading and removing of drying seed heads before they spread along the ground.

But even there you can thin them or pot them if they get too thick, or at worst, throw away the excess.

If you let them go too long though, or don't manage them at all, you'll find out you'll start to think of them as a weed rather than a flower.

Most people don't have so many ageratum that they can't remove the seed heads before they drop without it being a major chore.

Compelling Ageratum

Ageratum is a gorgeous, beautiful flower that is great for beginner and expert alike.

They can be used in a wide variety of circumstances; whether to fill a bed or to be placed in strategic locations around your yard and house.

Since they do well in almost any soil, it is a very versatile flower for any gardener looking at creative ways to add to or fill in challenging areas.

Ageratum are among the best flowers for doing that, and they will last outside from frost to frost. What more could you ask for out of a flower?

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

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