If your rose of Sharon doesn't get enough light, water, or enough phosphorus in the soil, flowers may not develop. Root rot from overwatering or overly wet conditions and pests like aphids can also cause issues with blooming.
No Rose of Sharon Flowers
Excessive shade and too little sun. Drought during an exceptionally dry summer. Rot caused by an exceptionally rainy summer or spring or because of soil that isn't draining. Inadequate phosphorus.
Rose of Sharon prefers full sun, meaning at least six hours of direct sunlight on most days. But it also can grow in partial shade. However, too much shade can minimize flowering and contribute to diseases, such as fungal issues. This shrub can grow in multiple soil types, including loamy, sandy, and clay soils.
Best Fertilizer for Rose of Sharon
An ideal fertilizer would be a slow-release formula with a balanced composition, such as 10-10-10 or 14-14-14. The second number, phosphorus can be higher than the rest, but a higher nitrogen level is not recommended.
Rose of Sharon grows at the rate of 24 inches (2 feet) per year. It is a slow grower that requires a lot of patience. To attain maturity, this plant needs about 4-6 years.
These shrubs are vigorous, hardy plants with few pest or disease problems with an average life span of 20-30 years. It could be that a few of your branches have succumbed to winter kill. Rose of Sharon prefers full sun, soil that is rich and moist, and is hardy to USDA zone 5 (i.e. Canadian zone 6).
The fact that rose of Sharon self-seeds so easily means it is also quite easy to propagate deliberately.
The magnesium in Epsom salts plays a major role in chlorophyll production, which is responsible for the green color in leaves. "Epsom salts can help prevent magnesium deficiency in roses, resulting in healthier foliage," says Harvell.
Fortunately, you can combine pruning with deadheading on this plant, which encourages bushy growth and gets rid of the seed pods at the same time. Because Rose of Sharon blooms on new growth every year, you can prune it in the fall without influencing the flowering.
The recommendation for applying Epsom salt to existing rose bushes is to either mix 1/2 cup of Epsom salts into the soil around the rose bush and water well or dissolve 1/2 cup of the salts in water and use the solution to water the soil around the rose bush.
By adding coffee grounds to your roses, you create a barrier that will keep pests away and allow your rose bushes to thrive. So if you're wondering whether coffee grounds are good for roses, the answer is a resounding yes! Coffee grounds are an inexpensive and readily available organic fertilizer for your roses.
For spectacular flowers and easy care, plant your Rose of Sharon in a spot with good drainage and full sun to partial shade. In northern climates, six or more hours of direct daily sun promotes maximum blooms.
This shrub is tolerant of many soil textures, moisture conditions, and acid to alkaline pH if it is in full or nearly full sun. However, it requires ample moisture and some protection from midday to afteroon sun to flower at it's best. The shrub will keep its upright form as it grows, so little pruning is required.
Indeed it is related to the flowering hibiscus. You may have noticed that the leaves of the Rose of Sharon, Hibiscus syriacus, are somewhat similar - although smaller with more of a serrated edge - to the leaves of the hibiscus. Like the hibiscus, it also flowers continually in the hot summer months.
There's no need to deadhead rose of Sharon. After three years (or when it's reached a height of around 1.5m), start pruning your rose of Sharon annually to keep in shape. If left unpruned, the outer branches can fall outwards from the weight of the leaves.
Poorly drained soil is one of the primary reasons for rose of Sharon leaves turning yellow. The moisture can't drain effectively, and soggy soil suffocates the roots, which causes drying and yellowing rose of Sharon leaves.
To propagate a rose of Sharon, dividing is not recommended, but taking cuttings can work well. In early to midsummer, trim lengths of six or seven inches, dip in rooting hormone, and plant in soilless mix, keeping evenly moist, covering if necessary, until new growth appears.
Prune by cutting 1/4” to 1/2” above an outward-facing bud eye (a small bump found where a leaf would meet the stem). New stems grow in the direction of the bud and the goal is to encourage them to grow outward, not inward. Make cuts at a 45-degree angle sloping away from the bud, allowing water to run off.
Baking Soda.
Dilute 1 teaspoon to 1 quart of warm, soapy water and spray on your roses' leaves. The baking soda will treat and prevent diseases like black spot, while the soap helps it stick, and is also mildly effective at smothering many insects pests.
It's also said to help seeds germinate and repel slugs and other garden pests. But unless your soil has a magnesium deficiency, the University of Minnesota Extension Service recommends against adding Epsom salt. Too much can harm your plants and soil.
Adding Epsom salts to soil that already has sufficient magnesium can actually harm your soil and plants, such as by inhibiting calcium uptake. Spraying Epsom salt solutions on plant leaves can cause leaf scorch. Excess magnesium can increase mineral contamination in water that percolates through soil.
Keep the cutting moist and away from direct sun- it should root in a month or two. Alternatively, propagate your Rose of Sharon cuttings in water. Some gardeners like to start the cuttings off in just a clear glass or plastic container of water rather than planted in compost.
However, when she gives birth, her baby is stillborn due to a lack of nutrition. These tragedies become transformative aspects of her life, which, in the end, shows her generosity when she feeds the starving old man the milk her body created for her baby.
Rose of Sharon is not a rose at all, or even distantly related to one. Rather, hibiscus, cotton and okra are its kin — all “Southern” plants, even though some species of hibiscus, like rose of Sharon, are perfectly at home in cold winter weather. They do like sun and hot summers, though.