As mid-summer approaches, this is the time when the black-eyed Susans start blooming all over the place. But some years, your flowers may not be looking as good as they should. Here are five reasons why your black-eyed Susans may not be blooming and what you can do about it.
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1. Too much water
Black-eyed Susans like moist but well-drained soil. They don’t like their feet to be wet for extended periods and may wilt in soggy soils. Water should be applied to the roots (the ground around the plant) and not poured directly on the crowns or leaves.
By watering deeply just once a week, you mimic the conditions these flowers prefer. As natives to the plains of the US, these flowers are used to occasional rainstorms that soak the soil, not frequent, shallow watering.
2. Competition from weeds
Weeds will compete with your plants for nutrients, water, and sunlight. Prevention is the best strategy not to have a weed problem in your garden. Mulching at least two inches deep around the base of the plant will help suppress weeds and retain moisture.
If you need ideas for mulch, check out this post, Best (Free!) Organic Mulches For The Home Garden, to find one to try.
If you have a weed problem, hand weeding and then applying mulch to prevent germination of new weed seeds is the best method. Avoid using chemical weed killers as they can leach into the roots of your plants and damage them.
3. Not enough sun
Black-eyed Susan grow best in full sun, preferring full sun or at least six hours of direct sunlight each day to bloom well. After all, they are plains natives, accustomed to long, hot summer days.
The plants will bloom most prolifically from mid-summer on once the days have warmed and lengthened.
If your flowers aren’t blooming, have a look at just how much (or how little) sunlight they’re getting.
The area you planted them initially may have been sunny during the spring, but have the surrounding trees filled out with leaves and now cast shade over the flowers?
If that’s the case, see if you can trim a few branches to let a little more light in.
If your garden has been shady from the start and your black-eyed Susan plants aren’t thriving, then it might be time to transplant them to another area of your yard where they’ll get more sunlight.
If you don’t have a spot for them that gets maximum sun during the day, then you can try growing them in containers that you can squeeze into a pocket of full sun.
For more tips on the sunlight requirement of black-eyed Susan, check out this post, Sun Or Shade For Black-Eyed Susan? (Plus tips for success).
4. Plants are too young
Black-eyed Susans take several months to grow from seed before they bloom, if not longer. Some varieties that are grown as annuals will bloom the first year from seed, while other perennial varieties prefer to overwinter before blooming.
For more on that, check out this article, Black-Eyed Susan: First Year Blooms & Other Flowering Questions.
One way to get around this is to buy young plants from a nursery. The plants will already be a few months old and should start blooming sooner than seeds when planted outside in the garden.
However, if you did buy plants, and they aren’t blooming yet: don’t fret. They need a little more time to settle into your garden, establish their root system, and put on new growth.
5. Disease or pest pressure
Black-eyed Susans are generally low-maintenance flowers, but they aren’t immune to occasional run-ins with pests and disease. If a plant is focused on fighting off pests or disease, then blooming falls down the list of priorities.
If your black-eyed Susan plants lack blooms, have a closer look at the plant to see if it’s dealing with outside stressors.
Powdery or downy mildew: These are two types of fungus that can cause black-eyed Susan plants to slow down flower production as the plant succumbs to disease pressure. The symptoms include stunted plant growth, yellowing leaves, and white powdery patches on the foliage. Leaves will often fall prematurely.
The best way to prevent this is adequate spacing between plants to encourage good air circulation.
Verticillium wilt: This is caused by a soil fungus that enters through the roots and spreads throughout the plant’s vascular system. Symptoms include yellowing and withering leaves, wilting plants, and lesions on the stems.
The best way to prevent this is to choose plants or seeds that are resistant to Verticillium wilt.
Black spot: Black spot is a common disease for black-eyed Susan, but it does not affect blooming. Black spot looks just like it sounds; small black spots pepper the plant leaves due to fungal growth, starting at the base of the plant and traveling up.
Fortunately, black spot is only a cosmetic disease and won’t harm your flowers or prevent them from blooming.
The best way to prevent this is by making sure there’s adequate space between plants, especially if you live in a humid area. Avoid overhead watering, too, since the fungus can spread through water splashed from one plant to another.
Aphids: Aphids are small, soft-bodied insects that feed on flower sap. A large infestation will cause black-eyed Susan leaves to curl and become disfigured, dropping petals at an alarming rate.
The best ways to prevent aphid infestations are to use an insecticidal soap spray or neem oil. You can also use a strong spray of water to knock the aphids off the plants, but you need to repeat the process frequently because even one missed aphid can make 80 new aphids in one week!
This article will help you diagnose these and other issues that might be stopping your flowers from blooming: What’s Wrong With Your Black-Eyed Susans? (Keep Your Plant Healthy).
For the full details of growing black-eyed Susans, bookmark this post, Black-Eyed Susan: A Complete Guide To Growing.