By Jennifer Poindexter
Are you in the market for a gorgeous, full plant that produces an abundance of blooms? If so, you should investigate growing Verbascum.
These plants are a wonderful way of adding color and texture to your garden or landscape. If you’d like to grow Verbascum around your home, you’re in the right place.
Allow me to walk you through the basics of growing this plant. I’ll share the necessary growing conditions, planting options, the process for caring for these plants, and also alert you to some potential issues.
If Verbascum is the right plant for you, here’s what you should know when growing it:
Growing Conditions for Verbascum
Verbascum is a bushy plant that produces long stems filled with vertical blooms. The plants reach heights around one to five feet tall and remain hardy in planting zones five through nine.
However, Verbascum are considered short-lived perennials at best. Most varieties are either biennials or annuals.
You should expect these plants to bloom between June and September. Annual varieties bloom in the first year whereas some biennial varieties won’t bloom until their second year.
When growing these plants, be sure to select a growing location with full to partial sunlight and well-draining soil.
They aren’t picky about soil type as long as it drains well. Keep in mind, the more sun these plants are provided, the more prolific their blooms are.
Take this information into consideration when deciding where you should plant Verbascum in your landscape.
How to Plant Verbascum
There are three common methods of propagation when growing Verbascum. The first method is to grow the plant from seed by directly sowing it into the permanent growing location.
Begin this process by selecting a growing location with ample sunlight and well-draining soil. You should plant seeds outdoors either at the end of summer or a month prior to the final spring frost.
If you plant seeds in the summer, they should overwinter and sprout the following spring. If you plant in the spring, the month of cold should be enough to allow the cold stratification process to occur and wake the seeds up in the coming weeks.
Till up the soil to approximately six to twelve inches deep. Create a hole that’s four times the length of the seed and place the seed in it. Lightly sprinkle the seeds with soil and gently water them. They need light to germinate.
Keep the soil damp around the seeds and wait two to four weeks for germination to occur. From there, add a layer of mulch and continue to water the plants as needed.
The next method for growing Verbascum plants is to start the seeds indoors. You should start the seeds two to three months prior to the last spring frost.
Select a container or growing tray that is filled with well-draining soil. Place the seeds in the container and lightly cover them.
Keep the soil evenly damp and at a consistent temperature around 75-degrees Fahrenheit. It should take anywhere from two to four weeks for germination to occur.
Some varieties do better when placed through the cold stratification process when grown indoors. Some seeds sprout fine without going through this process.
Whether you choose to emulate the cold stratification process indoors will be based upon your chosen variety and preference when starting seeds.
Once the seeds sprout, place them in a sunny growing location. They’ll need approximately sixteen hours of light per day. This may require supplemental lighting depending upon your situation.
If the seedlings become too large for their growing tray, transplant them to larger containers once they have two sets of true leaves.
Continue to keep the soil damp and the plants at a consistent temperature with adequate lighting until all threat of frost is over.
At this point, harden the seeds off for a week before transplanting them to their permanent growing location.
The final method for propagation is by root cutting. In the fall, dig up established Verbascum plants. Cut the main root of each plant into different sections.
Be mindful of which way the roots were growing in the ground because when you plant them in a container, they won’t grow upside down.
Place each root in a container that’s well-draining and filled with well-draining soil. Provide adequate moisture, light, and warmth. The roots should develop their own root systems in the coming months.
Once the plants are sturdy enough, you may harden them off and transplant them into their permanent growing area.
These are a few ways you may begin growing Verbascum. Pick the method which works best for your timing and skillset. Then introduce this plant to your landscape.
Caring for Verbascum
Verbascum must be cared for properly for this plant to thrive. To begin, you must keep the weeds under control. This is best accomplished by placing a layer of mulch around the plant and handpicking any remaining weeds which appear.
Also, you should provide an inch of water to this plant per week. This can be accomplished through rainfall or by watering the plant deeply.
When you apply more water, fewer days of the week, it encourages the roots to dig deeper into the soil to retrieve necessary water. This leads to sturdier root systems and healthier plants.
It’s important to fertilize Verbascum plants by using a slow-release fertilizer. For biennials, do this in the second-year in the early portion of spring.
These plants do grow taller, therefore, they may need staking to help provide necessary support. They also should be deadheaded when the blooms become spent to encourage more blooms.
Finally, when the leaves die back after a hard frost, go ahead and remove them. Then add a layer of mulch over the roots to protect them over the winter months to encourage biennial or short-lived perennial varieties to return the following year.
These are the things you should do to care for your Verbascum plants. These steps should help keep the plants healthier and sustain their beauty.
Garden Pests and Diseases Which Could Impact Verbascum
Part of raising a plant is understanding what you must be aware of to protect it in its growing area. Verbascum faces quite a few threats in the form of pests and diseases.
The most common diseases to impact Verbascum are downy mildew, powdery mildew, and root rot. These are fungal based issues which are best treated with a fungicide.
However, the best method is to deter these issues. You may avoid fungal issues by planting in warm growing locations and in well-draining soil.
Also, ensure there’s proper airflow around the plants to allow moisture to dry faster.
Should you encounter root rot, it’s best to remove the plant from the area it’s currently planted. You should allow the roots to dry out for a few hours prior to planting in a better growing location.
However, it is common for plants to die once they develop root rot.
The pests which commonly impact Verbascum are flea beetles, slugs, spider mites, and aphids. All of these threats may be treated with an insecticide or a strong spray of soapy water to dislodge both pests and their homes from the plants.
Slugs can be treated by either hand picking them or by sprinkling coffee grounds or diatomaceous earth around the base of the plants.
As you can see, prevention is key to protecting the health of your Verbascum. Yet, if pests or diseases find their way to your flowers, be ready to treat them accordingly to protect the longevity of your plants.
You now know which growing conditions are best for Verbascum. You’re also aware of how to plant them, care for them, and protect them.
Utilize this knowledge to add this plant to your landscape and enjoy the natural beauty it should supply to your home.
More About Growing Verbascum
https://hort.extension.wisc.edu/articles/common-mullein-verbascum-thapsus/
https://plants.ces.ncsu.edu/plants/verbascum/
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