Learn how to prune your salvias for the maximum bloom possible! We’ll go over the best time to prune, what tools to use, and how to properly execute the pruning so your salvias will look their best.
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What are Salvias?
Salvias are a diverse group of aromatic herbs in the mint family that are prized for their showy flower spikes and attractive foliage. Most salvias are native to the Americas, with a few species found in Africa, Asia and Europe. They range in size from 6-inch dwarf varieties to 5-foot-tall giants. Salvias are hardy in U.S. Department of Agriculture plant hardiness zones 5 through 10, although a few tender species only survive in zones 9 and 10.
When to Prune
Salvias are best pruned in late winter or early spring before new growth begins. This allows the plant to put its energy into new growth rather than repairing old wood.
How to Prune
Salvias are beautiful, drought-tolerant perennials that come in a variety of colors and sizes. They are easy to care for and make excellent cut flowers. Pruning Salvias is easy and only takes a few minutes. By pruning Salvias, you will encourage new growth and maximum bloom.
For Maximum Bloom
Start pruning in late winter or early spring, before new growth begins. For most varieties, the goal is to remove about one-third of the plant’s total height. But don’t get hung up on numbers—it’s more important to focus on creating a compact, well-branched plant.
When pruning, look for stems that are leggy, broken, or otherwise damaged. Remove these first, cutting them back to a point just above where they originate from a main branch or the plant’s crown. Then cut back the remaining stems by one-third to one-half their length, making sure to angle your cuts so that water won’t collect on the exposed surface (this can lead to disease problems).
Don’t be afraid to get rid of branches—the more you prune, the more blooms you’ll get.
For Size Control
Arching and upright salvias are often grown as annuals, but they can be kept as perennials in mild winter climates by pruning them to the ground each spring. This rejuvenation pruning also applies tocontainer-grown plants. Perennial salvias that bloom prolifically on new growth, such as ‘Indigo Spires’ and ‘May Night’, respond well to shearing after blooming to encourage compact, bushy growth and a second flush of flowers in late summer.
To keep a perennial salvia compact and bushy, cut it back to about 6 inches tall in late winter or early spring. When new growth begins to appear, pinch it back by another 2 to 3 inches to encourage branching. (Don’t prune Salvias grown as annuals; they need all their energy to produce an abundance of flowers.)
How to Fertilize Salvias
In order to keep your salvias blooming all season, you need to fertilize them regularly. The best way to do this is with a slow-release fertilizer that will provide nutrients to the plants over a long period of time. You can also use a water-soluble fertilizer, but be sure to follow the directions on the package carefully so that you don’t over-fertilize and damage the plants.
Salvias are heavy bloomers, so they need plenty of phosphorus in order to produce lots of flowers. A fertilizer with a ratio of 10-52-10 is ideal, but you can also use a general purpose fertilizer with a ratio of 10-10-10. Be sure to apply the fertilizer according to the package directions, and don’t forget to water it in well after application.
Pests and Diseases
Pests and diseases are a fact of life when you grow plants, and salvias are no exception. The good news is that most pests and diseases can be easily controlled with a little knowledge and effort. Here are some of the most common problems you may encounter when growing salvias:
Aphids: These small, soft-bodied insects are often seen in large numbers on the undersides of leaves, where they feed by sucking out plant juices. Aphids can distort new growth and weaken plants, and they also produce a sticky substance called honeydew that can attracting other pests such as ants. Aphids can be controlled with a strong stream of water or by spraying them with an insecticidal soap or neem oil solution.
Botrytis: Also called gray mold, this fungal disease thrives in cool, wet conditions and can quickly kill salvias. Botrytis usually starts as small brown spots on leaves or flowers that enlarge and turn grayish-brown. The best way to prevent botrytis is to provide good air circulation around plants and to avoid overhead watering. If you do get botrytis, remove infected leaves or flowers immediately and dispose of them in the trash. You can also treat plants with a fungicide such as neem oil or copper sulfate.
Powdery mildew: This fungal disease appears as a white powdery growth on the topsides of leaves. It usually shows up in late summer or early fall, when temperatures are warm during the day but cool at night. Powdery mildew doesn’t usually kill plants, but it can weaken them and make them more susceptible to other problems. The best way to prevent powdery mildew is to plant resistant varieties and to provide good air circulation around plants. You can also treat powdery mildew with a fungicide such as neem oil or sulfur dust.
rust: Rust is a fungal disease that appears as orange or brown spots on the topsides of leaves. It usually shows up in late summer or early fall, when temperatures are warm during the day but cool at night. Rust can weaken plants and make them more susceptible to other problems, but it usually doesn’t kill them outright. The best way to prevent rust is to plant resistant varieties and to provide good air circulation around plants. You can also treat rust with a fungicide such as neem oil or sulfur dust
There are many diseases that can affect salvias, but the most common are powdery mildew, root rot, and downy mildew.
Powdery mildew is a fungal disease that appears as a white powder on the leaves and stems of plants. It is often worse in humid or damp conditions. To prevent powdery mildew, make sure to space your plants so they have good air circulation and keep the leaves dry. If you see powdery mildew on your plants, you can remove infected parts and treat with a fungicide.
Root rot is caused by fungi that attack the roots of plants. This can be a problem in salvias because they have shallow roots. Root rot often makes plants look wilted even when they are watered, and it can kill plants if it is not treated. To prevent root rot, make sure to plant your salvias in well-drained soil and water them regularly. If you see signs of root rot on your plants, you can try to save them by carefully removing the affected roots and replanting in fresh soil.
Downy mildew is another fungal disease that affects salvias. It appears as yellow or brown spots on the leaves, and it can cause the leaves to curl up or drop off the plant. Downy mildew is often worse in humid conditions. To prevent downy mildew, water your plants from below so the leaves don’t stay wet for long periods of time. You can also treat affected plants with a fungicide