Minus some advance planning, fall usually spells the end of the garden. But if planted in spring, dahlias will flower non-stop through autumn. Lately, I’ve been waking up to crisp mornings only to discover more and more blooms. Who knew October could bring so many fresh flowers?.
With their vibrant, brightly colored blooms that come in every hue, dahlias are one of the showiest flowers for gardens. But how do you identify dahlia plants by their leaves alone, before those spectacular blossoms appear? Here’s what to look for.
Dahlia Leaf Characteristics
Dahlia leaves have some distinct features that set them apart from other plants
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Opposite growth pattern – Leaves emerge directly across from each other along the stems
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Pinnately compound shape – Leaves are made up of smaller leaflets arranged on either side of a central stem,
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Ovate, oblong or lanceolate leaflets – Individual leaf segments have an oval, elongated, or lance-head shape.
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Lobed or toothed edges – Leaf margins are serrated with lobes or teeth.
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Varying colors – Leaves may be green, burgundy-red, or nearly black depending on variety.
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Alternate branching – Stems branch and leaves grow in an alternating pattern.
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Thin texture – Leaves have a delicate, papery thinness.
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Glossy appearance – Healthy dahlia leaves have a waxy sheen.
Dahlia leaves exhibit a great range in size. On some compact varieties, leaves stay under 3 inches wide, while leaves of giant dahlias can reach 12 inches across! But all share the features above.
Parts of a Dahlia Leaf
A dahlia leaf consists of three main parts:
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Petiole – The stalk attaching the leaf to the stem. It may be green, red, or purple.
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Leaflets – The small individual blades that make up the compound leaf. A mature leaf can have 5-9 leaflets.
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Central vein – The central stem that supports all the leaflets, like the spine of a book.
How Dahlia Leaves Grow
Dahlia leaves emerge from buds at the tips of stems and branches. The first pairs of leaves are simple leaves made of a single leaf blade. As the plant matures, subsequent leaves become pinnately compound, with 3, 5, 7 or more leaflets.
Mature dahlia plants grow leaves in an alternate pattern, with each new leaf emerging singly on alternating sides of the central stem. The leaves unfurl from reddish or purplish buds, lightening to green.
Changes Throughout the Season
Dahlia leaf color, size, and shape changes throughout the growing season:
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Spring – Leaves are small and sparse. Just a few sets of simple leaves with rounded segments appear.
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Summer – Rapid growth produces many large, compound leaves. The dark green color is most vivid now.
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Fall – Cooler temperatures cause leaves to turn more yellow, red, or brown. Hard frosts kill the foliage.
Comparing Dahlia Leaves to Other Plants
Some key differences help distinguish dahlia leaves from other plants:
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Hosta leaves are solid green with parallel veins, not compound.
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Clematis leaves are opposite but have smooth, untoothed edges.
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Tomato leaves are pinnately compound but don’t have glossy or colorful foliage.
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Maple leaves are also opposite and compound but have pointed lobes and autumn color.
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Columbine leaves are compound but irregularly lobed, not ovate leaflets.
Signs of Dahlia Leaf Problems
Unhealthy dahlia leaves exhibit certain issues:
- Wilting or drooping
- Holes or chewed areas
- Black, tan, or brown spots
- Yellowing
- Distorted growth
- White powdery coating
These can indicate problems like pests, diseases, underwatering, overwatering, or nutrient deficiencies. Address issues promptly to restore good leaf health.
When Leaves Appear Without Flowers
If a dahlia plant has lush green leaves but no flowers, it’s likely one of these factors:
- Too much nitrogen fertilizer
- Not enough sunlight
- Excessive pruning
- Insufficient chilling hours
- Immature plant or tubers
- Damage from late frosts/freezes
Reduce fertilizer, improve light exposure, avoid overpruning, and protect from cold temperatures to help initiate blooming. Also allow young plants time to establish.
Using Leaves for Identification
When buying dormant dahlia tubers or young plants, use the emerging leaves to determine if you have the correct variety before waiting for it to bloom. Compare leaf color and shape to the labeled description.
For mature plants that have lost their tags, leaf characteristics can help narrow down possible dahlia identities. Reference leaf photos from online catalogs to match your plant as closely as possible.
Key Takeaways on Dahlia Leaves
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Look for opposite, pinnately compound leaves with ovate, oblong, or lance-shaped leaflets and toothed edges to identify dahlias.
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Leaves may be green, red, purple, or blackish depending on cultivar. All have a glossy texture.
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Watch for chewed, spotted, yellowed, or distorted leaves, which indicate a problem needing treatment.
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Use leaf shape, color, and size to help identify specific dahlia varieties.
With their fern-like foliage and fabulous flowers, dahlias are the stars of any late summer garden. Learning to recognize dahlia leaves makes it easier to care for and appreciate these plants from the moment they emerge in spring.
FLOWERS AS BIG AS A FOOT
Still, it goes without saying that the most notable feature of all dahlias are the flowers. These can range in diameter from 2 inches to almost one foot. And among these, there are specific dahlia types, each with its own specifications. For example, there are species with single, double and semi-double petals. And there are unusual shapes like spherical or cactus. There are also types that resemble flowers such as anemones, peonies or orchids.
Waterlily dahlia ‘Pam Howden’
Notwithstanding the variety, one thing all dahlia types have in common is their dazzling color. There are a lot of different colors of these flowers, like pink, red, scarlet, orange, purple, and yellow. Moreover, the flower petals often come painted with strips or tips of another color. (There are also creamy ones as well as many brilliant white species. ).
That being said, how do you choose when there are so many? One way is to learn about the most common types. You may be surprised to find that some don’t look like the ‘typical’ dahlia.
SO MANY TYPES, SO LITTLE TIME
Dahlias are classified as tender perennials, meaning they may be annual or perennial, depending on the climate. They typically start blooming in August with other late-summer flowers. The best thing about them, though, is that they bloom until the first frost, which is close to Thanksgiving.
Even though they are known for having tall stems and huge flowers, the plants come in a lot of different sizes and shapes. Dahlias can be pretty short or very tall. The ones I remember from my childhood were very tall. Planting the tubers is easy. Just dig a hole 6 to 8 inches deep and drop them in with the ‘eyes’ facing up. Three or more tubers per hole usually gives the most colorful effect.
How to Identify Dahlia Viruses and Prevent Virus Infection from Destroying Your Plants
FAQ
What are the characteristics of dahlia leaves?
What are the identifying features of dahlias?
Is there an app to identify dahlias?
What is the shape of the leaves on a dahlia plant?
How do you know if a dahlia is growing?
Avoid planting dahlia tubers that appear wrinkled or rotten. Pink “eyes” (buds) or a little green growth are good signs. Plant large dahlias and those grown solely as cut flowers in a dedicated plot where they will be free from competition from other plants.
How tall should a dahlia grow?
When your dahlia reaches approximately 12 inches tall or has three sets of leaves, Rowe recommends pinching off the center shoot to encourage side branching, which will create a stronger plant with more blooms. Speaking of dahlia blooms: It’s important to cut and enjoy them.
How do you know if a dahlia plant has a fungal infection?
Other symptoms of a fungal infection include white or gray powdery spots on the leaves, as well as fungal spores on the underside of the leaves. If you suspect your dahlia plants have a fungal infection, it is important to take action quickly.
What is a dahlia plant?
What are dahlias? Hailing from Central America, the Dahlia genus includes roughly 40 flowering plants that belong to the Asteraceae family, which also includes beauties, such as sunflowers and chrysanthemums — in fact, dahlias are very similar to chrysanthemums, except they tend to be smaller.