Growing snapdragons seems like it should be a snap – just plant some seeds or flats of young plants and in no time you’ll have big, bushy plants, right? Sometimes it works out just that easily, but other times your gorgeous bloomers can start to show signs of stress, like wilting. Wilting snapdragons is definitely a red flag for growers and there are many reasons they may be doing this. Read on to learn the main reasons for snapdragons that wilt.
To understand why snapdragons are wilting, it’s important to understand what wilting really is. When a plant wilts, it’s because of a lack turgor pressure within the plant’s cells. Plants need a certain amount of water within their cells to maintain their functions, much like animals; but unlike animals, they also use that water to help maintain their shape.
When a plant is lacking water, either because there isn’t enough available due to a drought or because there’s a blockage in vascular tissue from a disease like Verticillium wilt, the plant will continue to try to respirate, which causes it to release water into the atmosphere. But since it can’t take the same amount of water back in as it just expelled, it eventually starts to dehydrate. After enough time, wilting becomes obvious. Some causes are pretty easy to fix, others are fairly insidious.
If your snapdragons are wilting, there could be a number of reasons. Let’s go over some of the most common:
Available water. When your plant can’t soak up enough water from the environment, it will start to show. Wilting is the first sign of a lack of water in plant cells, due to a lack of turgor. Water snapdragons in beds deeply when the top two inches of the soil are dry, snapdragons in pots should be watered daily during hot weather.
Downy mildew. If the leaves of your plant are turning yellowish as they wilt and the undersides have a downy or fuzzy covering, they may be infected with downy mildew. This fungus prefers cool, wet weather. Early infections may be able to be treated with a fungicide, but if the fungus is throughout the plant, you’re better off to get rid of it, sterilize the soil and start again. Clean up all plant debris, since the fungal spores can survive and repopulate from here.
Root rot. There are two main types of root rot in snapdragons, Pythium and Rhizoctonia. Pythium tends to attack the roots, where Rhizoctonia tends to attack the base of the plant, near the soil line. You may notice a lesion there if you uproot your ailing plant. These plants will look otherwise normal and then just suddenly collapse. There is no cure, but you can prevent future outbreaks by increasing drainage to the site or container and reducing the frequency of waterings, since the presence of excessive moisture encourages these fungi.
Wilt fungus. Verticillium is a notorious problem child among gardeners. If your snapdragons are growing as annuals and they contract it late in the year, you may simply ignore the fungal disease and let it play out, then destroy the infected plant material and sterilize your site. Since Verticillium often kills slowly as it clogs snapdragon vascular tissues, you can help your plant live longer by watering only as necessary and removing infected tissues. When wilt strikes earlier in the year, removing the sick plant, sterilizing the soil and starting again is a much better option. There is no cure.
Anthracnose (fungus – Colletotrichum antirrhini): Large, light colored spots occur on leaves and stems. Spots frequently have black or brownish dots near centers. Entire leaves may be killed and often the whole plant dies from stem girdling. Spore bearing pustules appear as minute black pimples in the spots. Under a microscope, dark brown, hair-like outgrowths are visible on these pustules. Pull and burn affected plants as soon as disease appears. Spray with recommended fungicides to prevent spread. Water by irrigating surface of soil rather than wetting the foliage. Take cuttings only from healthy plants.
Rust (fungus – Puccinia antirrhini): Brown, powdery pustules appear on lower surface of leaves. Plants may be stunted and even killed. Propagate from healthy plants or grow from seed. Control insects that carry the fungus spores from one plant to another. Plants should be spaced so that they have plenty of air. Avoid wetting the foliage when watering. Keep greenhouse temperature above 70 o F for several days and not below 60 o F at night. Where foliage is wet when watering, spray at weekly intervals with recommended fungicide. Good coverage is necessary for best results. Some resistant varieties are available.
Blight (fungus – Phyllosticta antirrhini): Cream colored or light brown circular spots appear on the leaves, sometimes surrounded by circles of other colors. The small black fruiting bodies of the fungus develop on the upper surface of the leaves at the center of the spots. Ash-gray spots covered with the black pycnidia develop on stems. These spots enlarge rapidly and turn dark brown. If the spots entirely encircle the stem, the plants wilt and frequently die. All parts of the plants in diseased beds should be removed and burned at the end of the season. Spray with recommended fungicides. Keep leaves dry and space more widely.
Wilt (fungus – Verticillium albo-atrum): Infected plants wilt slowly. At first, only certain branches show wilting. Plant in disease-free soil or sterilize soil with steam. When only a few plants appear infected, remove these together with surrounding soil. Water as little as possible to obtain good growth. Cotton burs used for mulch in West Texas may carry the fungus and should be well composted.
Gray Mold (fungus – Botrytis cinerea): This fungus causes a wilting of the flower stalks. A development of light brown areas on the stems at the base of the flower clusters. Under moist conditions, the spores of the fungus may develop in light brown or gray masses. Avoid excess humidity. Cut off and burn infected flower-stalks as soon as they are detected. Keep greenhouse and garden plantings free from debris because the fungus can live as a decay fungus under such conditions and its spores may be blown to living plants. Spray with recommended fungicides after the plants have been cut back to force a second crop.
Powdery Mildew (fungus – Oidium spp.): Largely confined to greenhouse-grown snapdragons, this mildew forms a white, powdery coating on both leaf surfaces and young stems. Spray with recommended fungicide.
Leaf Spot (fungus – Cercospora antirrhini): Previously reported only from Guatemala, this leaf spot was found in Florida in 1958. Spots are circular, 0.5 to 5 mm in diameter, dingy gray to white. No control measures have been developed but fungicides that control Cercospora spp. on other crops might be effective.
Root Knot Nematodes: (See section on Root Knot Nematodes)
Southern Blight: (See section on Southern Blight)
Stem and Root Rot: (See section on Stem and Root Rot)
Cotton Root Rot: (See section on Cotton Root Rot)
Snapdragons get their name from the shape of the flowers, which children love to squeeze to make the “dragon” open and close its mouth. These colorful annuals come in just about every shade and combination of pink, red, and yellow you can imagine. The mainstay of old-fashioned flower gardens, they play just as important a role in today’s modern gardens.
Planting and Care for Snapdragons
Snapdragons are easy to grow. You will have success if you grow them in well-drained garden soil. In most locations snapdragons need full sun, but because they stop flowering when it gets too hot, they prefer partial shade in hot, sunny climates.
Snapdragons are not heavy feeders, so if you add compost to the soil that might be all the food they need to grow strong and bloom profusely.
You can either sow snapdragon seeds indoors ten weeks before the last frost date or buy transplants. (In Southern California and similarly hot places gardeners sow their snapdragon seeds in fall or winter for spring blooming.) Plant seedlings of small varieties six to eight inches apart taller types need twelve inches between plants.
Spacing depends on the ultimate size of your snapdragons, which can be anywhere from eight inches to four feet tall.
Water regularly if there’s not enough rain, and remove any weeds. Mulching will help conserve water and keep the weeds down. If you remove spent flowers your plants will keep blooming until the weather gets too hot. When the plants stop producing flowers cut the stems down to about five inches from the ground. Water well, and you are likely to get another flush of flowers before frost kills the plants.
Snapdragon Pests and Diseases
Snapdragons are vulnerable to a number of fungal diseases. Good air circulation in the garden, avoiding overhead watering, and keeping the garden area clean will help avoid these problems.
Landscape Uses and Snapdragons
Small snapdragons are delightful bedding plants, mixing well with other annuals in the flower garden. Tall varieties are excellent in flower arrangements, along a fence, and planted in the back of a border. You may need to stake the tall, old-fashioned varieties.
Some gardeners let their snapdragons go to seed and collect the seeds. The best way to ensure you get the snaps you want, however, is to buy transplants or seeds from a reputable source.
Learn More About How to Grow Snapdragons?
Snapdragons Galore has got plenty of photos of snapdragons.
Here’s a great .pdf file all about Snapdragons.
How much water do they [Snapdragons] need?
suman prasad says
I just planted snap dragons in my garden. A few of them have already wilted and seem to be dying inspite of watering, fertilizing. What could be the reason?
Fungus such as Pythium or powdery mildew as well as tomato spotted wilt virus are common pests for the snapdragon. These illnesses leech the snapdragon's resources and nutrition at the same time, causing its leaves to wilt from a combination of malnutrition and exhaustion. If mildew or fungus should appear, dry them out by watering only the soil beneath the plant and leaving the foliage dry. Prune already dead areas from the snapdragon to help keep it strong and administer a liquid fertiliser to help boost nutrient levels.