Dahlias
Latin Name Pronunciation: dah'lee-uh
Dahlias offer flamboyant flowers on lush plants from summer through fall, right up to the first frost. Fully hardy to zone 8, these hybrids of species native to Mexico and Colombia may overwinter in Zone 7 with a thick blanket of mulch. Gardeners in colder zones can get a head start by planting tubers in pots 4 to 6 weeks before the last spring frost date. Plant tubers several inches deep in a light, soilless potting mix and water sparingly until new growth appears, then more freely. Place pots in a sunny window or under grow lights, and then plant outside after danger of frost has passed. Taller varieties will need staking, with stakes placed carefully so as not to injure the tuber or roots. If planting is delayed (either indoors or in the ground), store the tubers in their bags in a cool, dry, dark location.
Light/Watering
Dahlias can hold their own among:
Early Spring
Dahlia Bulbs (tubers) are available in many catching colors and exotic shapes to give you a spectacular show of color in borders, beds or even containers. They have long been a favorite with gardeners as they are hardy and low maintenance. Dahlias will yield beautiful blooms from mid-summer through fall.
When to Plant your Dahlia Bulbs:
Unlike other bulbs such as Tulips, Dahlias like warm soils so plant Dahlia bulbs during the warmer and longer days of spring. Dahlias are usually planted about the same time you would plant your vegetable patch. Dahlia bulbs can be planted as late as mid-June in most parts of the country.
Where to Plant you Dahlia Bulbs:
Dahlia is an accommodating plant - it will grow almost anywhere! Dahlias will thrive in full sun but can tolerate some partial shade - the more sun, the bigger the flowers. Try to select a location that receives at least 6 hours of sun, sheltered from the wind and with, and this is vital, good drainage.
How to Plant your Dahlia Bulbs:
Dig a hole twice as deep and wide as the Dahlia bulb. Put the tuber in the hole with the “eye” on the tuber facing up. The eye is the point on the shoulder, or crown, of the tuber from which the plant grows. If you are planting a number of dahlias in the same location, they should be separated by about 2 feet to give each plant room to grow. The shorter varieties can be planted closer together. Plan for the rows to be 3 to 5 feet apart depending on the size of the plant. Fill in with soil to just cover the top of the bulb. As you begin to see new growth appear, cover again with soil. Covering the stem gradually will allow the stem to strengthen so it can support the flowers. Unless it is a very dry spring, it is not be necessary to water at the time of planting. The tubers will begin growing with the warmth and moisture in the soil. It is vital that they form a root system early in their planted life to assure a strong and healthy plant. Watering at the time of planting may encourage rot but as soon as your Dahlias are growing above the ground, water deeply to encourage strong roots.
How to Care for your Dahlia Bulbs:
Young dahlia plants do not need a lot of water; in fact, excessive water can lead to rotting of the plant. For larger plants, a good rule of thumb is to water if the rainfall is less than one inch in seven days. Pots require more regular watering. As the plant grows, remove any broken or damaged foliage. Good air circulation, especially near the ground is needed by the plants to prevent powdery mildew. Once the plants are several feet high the lower leaves can be removed to increase air circulation. Your dahlias will continue to bloom prolifically right up until frost. A heavy frost will kill the plant so you may want to dig the half a dozen or more tubers the plant has produced. Those tubers can then be stored and grown next spring!
Dahlia Bulbs (tubers) are available in many catching colors and exotic shapes to give you a spectacular show of color in borders, beds or even containers. They have long been a favorite with gardeners as they are hardy and low maintenance. Dahlias will yield beautiful blooms from mid-summer through fall. When to Plant your Dahlia Bulbs: Unlike other bulbs such as Tulips, Dahlias like warm soils so plant Dahlia bulbs during the warmer and longer days of spring. Dahlias are usually planted about the same time you would plant your vegetable patch. Dahlia bulbs can be planted as late as mid-June in most parts of the country. Where to Plant you Dahlia Bulbs: Dahlia is an accommodating plant - it will grow almost anywhere! Dahlias will thrive in full sun but can tolerate some partial shade - the more sun, the bigger the flowers. Try to select a location that receives at least 6 hours of sun, sheltered from the wind and with, and this is vital, good drainage. How to Plant your Dahlia Bulbs: Dig a hole twice as deep and wide as the Dahlia bulb. Put the tuber in the hole with the “eye” on the tuber facing up. The eye is the point on the shoulder, or crown, of the tuber from which the plant grows. If you are planting a number of dahlias in the same location, they should be separated by about 2 feet to give each plant room to grow. The shorter varieties can be planted closer together. Plan for the rows to be 3 to 5 feet apart depending on the size of the plant. Fill in with soil to just cover the top of the bulb. As you begin to see new growth appear, cover again with soil. Covering the stem gradually will allow the stem to strengthen so it can support the flowers. Unless it is a very dry spring, it is not be necessary to water at the time of planting. The tubers will begin growing with the warmth and moisture in the soil. It is vital that they form a root system early in their planted life to assure a strong and healthy plant. Watering at the time of planting may encourage rot but as soon as your Dahlias are growing above the ground, water deeply to encourage strong roots. How to Care for your Dahlia Bulbs: Young dahlia plants do not need a lot of water; in fact, excessive water can lead to rotting of the plant. For larger plants, a good rule of thumb is to water if the rainfall is less than one inch in seven days. Pots require more regular watering. As the plant grows, remove any broken or damaged foliage. Good air circulation, especially near the ground is needed by the plants to prevent powdery mildew. Once the plants are several feet high the lower leaves can be removed to increase air circulation. Your dahlias will continue to bloom prolifically right up until frost. A heavy frost will kill the plant so you may want to dig the half a dozen or more tubers the plant has produced. Those tubers can then be stored and grown next spring!
Dahlias offer flamboyant flowers on lush plants from summer through fall, right up to the first frost. Fully hardy to zone 8, these hybrids of species native to Mexico and Colombia may overwinter in Zone 7 with a thick blanket of mulch. Gardeners in colder zones can get a head start by planting tubers in pots 4 to 6 weeks before the last spring frost date. Plant tubers several inches deep in a light, soilless potting mix and water sparingly until new growth appears, then more freely. Place pots in a sunny window or under grow lights, and then plant outside after danger of frost has passed. Taller varieties will need staking, with stakes placed carefully so as not to injure the tuber or roots. If planting is delayed (either indoors or in the ground), store the tubers in their bags in a cool, dry, dark location.
Light/Watering
- Dahlias are at their best when grown in full sun in the North, afternoon shade in the South.
- Do not water until growth appears above the ground; once plants are established, a deep watering twice a week will get them through summer dry periods.
- Soil temperature at planting should be 60°F.
- Dahlias prefer an open, well-drained soil with a pH of 6.5 to 7.0.
- A fertilizer low in nitrogen is best (5-10-10, for example), first applied 30 days after planting and then side-dress monthly. Do not overfeed, and avoid high-nitrogen, water-soluble products.
- Aphids can be killed by spraying with insecticidal soap or Neem.
- If Dahlia stems show breakage and wilting, borers may be present; to deter, keep weeds away from the planting, and cut off and destroy any larvae-infested stems.
- If leafhoppers are a problem, spray plants with a mix of one tablespoon isopropyl alcohol to one pint of insecticidal soap, repeating 3 times at 3-to-5-day intervals.
- Watch for spider mites during hot, dry weather; spray leaves with Neem or a forceful jet of cold water, particularly on the undersides.
- If powdery mildew appears as a whitish coating on the leaves, spray with wettable sulfur or other appropriate fungicide. Next year, give plants more space for better air circulation.
- If stems rot at the soil line or plants suddenly wilt and die, a bacterial or fungal agent may be present. Remove and destroy any affected plant parts; avoid this problem by planting in well-drained, light soil and do not overwater. Keep mulch several inches away from the plant stems.
Dahlias can hold their own among:
- Roses
- Oriental Lilies
- Ornamental Goldenrod (Solidago)
- Fall-blooming Asters
- Many annuals
- Dahlias make excellent cut flowers; to achieve nice stems for cutting and bushier, compact plants, pinch out the center shoot just above the third set of leaves. These shoots can be rooted, if desired.
- To get the most out of your cut flowers, place them in very hot water (160°F) until it cools.
- If dead flowers are diligently removed, flowering will continue until the first frost.
- To develop large, exhibition-size blooms, remove side buds and allow only one bud per stem to develop.
- Dahlia tubers may be divided in spring or fall. Use a sharp knife to cut the tubers apart—only those tubers with an eye (a dormant bud) will grow stems.
- Not all tubers will have eyes, so cutting a clump into halves or quarters is safer than cutting off individual tubers.
- Allow roots to dry for a day before storing or planting.
- If you have more than one variety, label each tuber.
- Wait a few days after the foliage is blackened by frost before digging the tubers to store for the winter. If plants are in a frost-free area, dig by mid-November.
- Cut the stalk to 4–6″ tall, rinse off the soil, and allow the clump to air dry under cover for 24 hours.
- Line cardboard boxes or terra-cotta pots with newspaper and layer tubers with barely moist sawdust, sand, or peat. Do not store in plastic.
- Keep boxes cool (40–50°F) and dry for the winter in a dark spot
- Check for rot or shriveling on a monthly basis; if shriveling occurs, mist the packing material lightly with water.
- Remove all old foliage from the garden area.
Early Spring
- Dahlia tubers may be divided now.
- Plant tubers 6″ deep when soil has warmed after frost or start early indoors in pots.
- Water tubers sparingly once after planting and then do not water until new growth appears.
- Fertilize with 5-10-10 when growth reaches 2″ tall.
- Continue feeding every month, side-dressing with 5-10-10.
- Watch for aphids and other insect pests and treat accordingly.
- Keep weeds away from plantings.
- Mulch if desired but keep material away from crowns and stems.
- Water thoroughly if season is dry.
- Tie larger varieties to stakes as they grow.
- Pinch out center shoots just above the third set of leaves, or leave shoots and remove side buds for extra-large flowers.
- Watch for signs of fungal wilt and remove and destroy affected plant parts if it occurs, then sterilize pruners with bleach solution.
- Monitor plants for aphids and other insect pests and treat accordingly.
- Continue to water if conditions indicate, and deadhead diligently for continuous bloom.
- Mulch plants heavily if overwintered in the ground in Zones 7 and above.
- Further North, wait until a few days after frost has killed the foliage, then dig tubers, air dry under cover and store cool, dry and dark in newspaper-lined cardboard boxes or clay pots. Cover tubers with lightly moistened sand or peat. Tubers may be divided before storing if desired. If you have more than one variety, label each tuber.
Dahlia Bulbs (tubers) are available in many catching colors and exotic shapes to give you a spectacular show of color in borders, beds or even containers. They have long been a favorite with gardeners as they are hardy and low maintenance. Dahlias will yield beautiful blooms from mid-summer through fall.
When to Plant your Dahlia Bulbs:
Unlike other bulbs such as Tulips, Dahlias like warm soils so plant Dahlia bulbs during the warmer and longer days of spring. Dahlias are usually planted about the same time you would plant your vegetable patch. Dahlia bulbs can be planted as late as mid-June in most parts of the country.
Where to Plant you Dahlia Bulbs:
Dahlia is an accommodating plant - it will grow almost anywhere! Dahlias will thrive in full sun but can tolerate some partial shade - the more sun, the bigger the flowers. Try to select a location that receives at least 6 hours of sun, sheltered from the wind and with, and this is vital, good drainage.
How to Plant your Dahlia Bulbs:
Dig a hole twice as deep and wide as the Dahlia bulb. Put the tuber in the hole with the “eye” on the tuber facing up. The eye is the point on the shoulder, or crown, of the tuber from which the plant grows. If you are planting a number of dahlias in the same location, they should be separated by about 2 feet to give each plant room to grow. The shorter varieties can be planted closer together. Plan for the rows to be 3 to 5 feet apart depending on the size of the plant. Fill in with soil to just cover the top of the bulb. As you begin to see new growth appear, cover again with soil. Covering the stem gradually will allow the stem to strengthen so it can support the flowers. Unless it is a very dry spring, it is not be necessary to water at the time of planting. The tubers will begin growing with the warmth and moisture in the soil. It is vital that they form a root system early in their planted life to assure a strong and healthy plant. Watering at the time of planting may encourage rot but as soon as your Dahlias are growing above the ground, water deeply to encourage strong roots.
How to Care for your Dahlia Bulbs:
Young dahlia plants do not need a lot of water; in fact, excessive water can lead to rotting of the plant. For larger plants, a good rule of thumb is to water if the rainfall is less than one inch in seven days. Pots require more regular watering. As the plant grows, remove any broken or damaged foliage. Good air circulation, especially near the ground is needed by the plants to prevent powdery mildew. Once the plants are several feet high the lower leaves can be removed to increase air circulation. Your dahlias will continue to bloom prolifically right up until frost. A heavy frost will kill the plant so you may want to dig the half a dozen or more tubers the plant has produced. Those tubers can then be stored and grown next spring!
Dahlia Bulbs (tubers) are available in many catching colors and exotic shapes to give you a spectacular show of color in borders, beds or even containers. They have long been a favorite with gardeners as they are hardy and low maintenance. Dahlias will yield beautiful blooms from mid-summer through fall. When to Plant your Dahlia Bulbs: Unlike other bulbs such as Tulips, Dahlias like warm soils so plant Dahlia bulbs during the warmer and longer days of spring. Dahlias are usually planted about the same time you would plant your vegetable patch. Dahlia bulbs can be planted as late as mid-June in most parts of the country. Where to Plant you Dahlia Bulbs: Dahlia is an accommodating plant - it will grow almost anywhere! Dahlias will thrive in full sun but can tolerate some partial shade - the more sun, the bigger the flowers. Try to select a location that receives at least 6 hours of sun, sheltered from the wind and with, and this is vital, good drainage. How to Plant your Dahlia Bulbs: Dig a hole twice as deep and wide as the Dahlia bulb. Put the tuber in the hole with the “eye” on the tuber facing up. The eye is the point on the shoulder, or crown, of the tuber from which the plant grows. If you are planting a number of dahlias in the same location, they should be separated by about 2 feet to give each plant room to grow. The shorter varieties can be planted closer together. Plan for the rows to be 3 to 5 feet apart depending on the size of the plant. Fill in with soil to just cover the top of the bulb. As you begin to see new growth appear, cover again with soil. Covering the stem gradually will allow the stem to strengthen so it can support the flowers. Unless it is a very dry spring, it is not be necessary to water at the time of planting. The tubers will begin growing with the warmth and moisture in the soil. It is vital that they form a root system early in their planted life to assure a strong and healthy plant. Watering at the time of planting may encourage rot but as soon as your Dahlias are growing above the ground, water deeply to encourage strong roots. How to Care for your Dahlia Bulbs: Young dahlia plants do not need a lot of water; in fact, excessive water can lead to rotting of the plant. For larger plants, a good rule of thumb is to water if the rainfall is less than one inch in seven days. Pots require more regular watering. As the plant grows, remove any broken or damaged foliage. Good air circulation, especially near the ground is needed by the plants to prevent powdery mildew. Once the plants are several feet high the lower leaves can be removed to increase air circulation. Your dahlias will continue to bloom prolifically right up until frost. A heavy frost will kill the plant so you may want to dig the half a dozen or more tubers the plant has produced. Those tubers can then be stored and grown next spring!
Plant InformationThe Biltmore garden experts chose this one for sheer beauty. The magnificent, almost camellia-like flowers are new in dahlias, and the coloring on this one is a knockout.Why Gardeners love Dahlias (See combination photo below.) Dahlias are one of the most rewarding summer flowers of all. They're really easy to grow with spectacular results. If you know them, you know all about it. If you don't, here is the information you need. Prepare to become 'hooked.'
First of all, Dahlias are great for cutting, as you can see in the large top photo of an arrangement showing a lavish deep red dahlia right next to a large, voluptuous rose.
Dahlias are native to Mexico, but there's about as much resemblance between the original and the Dutch hybrids as there is between an old toy car and a brand new Mercedes. Dahlias for today's gardeners offer a really big gardening treat.
The 'bulbs' are actually tubers, and look a lot like peony roots--sort of like a bunch of carrots. The plants grow quickly and some grow quite tall, always with lush deep green foliage.
Types of Dahlias. These plants have been hybridized into various heights from short bedding plants to tall bushy ones. But they are officially categorized by flower type or shape. The term, 'Dinnerplate Dahlia' is probably the most famous description, and though all gardeners use the term, it is not an official classification. 'Dinnerplates' are, simply put, the large plants with the huge flowers. The always-double flowers are up to 8', sometimes a whopping 10' across, so the name makes sense.
Photos A and C are examples of Dinnerplate Dahlias. As you can see, they come in both solids and bi-colors.
Photo B shows a whole border of tall dahlias in the garden.
Here are the official classifications:
'Decorative Dahlias' This group includes the Dinnerplates and also other taller (to 4 ft.) plants with double, chrysanthemum-like flowers. The famous 'Shogun Dahlias' are as tall as Decoratives, but have very heavy bloom of smaller bi-colored flowers for gardeners who want a large bushy plant covered with color.
'Cactus Dahlias' are the ones with the cactus-like blooms, often in super-bright bi-colors, always with the rolled, pointed petals. Like other groups, Cactus Dahlias can be of various heights, as long as they have 'cactus' flowers.
'Gallery Dahlias' are a newer group of shorter plants with flower-types of the Decoratives and Cactus groups. The Gallery group is named with terms from the art world including famous artists' names.
'Butterfly' or 'Impression Dahlias' are what the Dutch call 'bedding dahlias. They stay short, and are perfect for pots or borders. The names in this group all begin with 'F' like 'Futuro' and 'Fantastico'. The flowers are wide-open and daisy-like for a really colorful display of their brilliant hues. If well cared-for, watered, and dead-headed, they bloom constantly all season, making great masses of color.
There are other groups such as 'Ball Dahlias' and 'Pom Pom Dahlias' with spherical blooms, 'Colarette Dahlias' with uneven rows of petals creating a 'collar' effect--the varieties go on and on. Growing all of them is essentially the same, and best of all, it's easy.
Growing Dahlias: All the gardener needs to do is plant the tubers after spring frosts in good garden soil with full sun. It's best to position them against a wall or be ready to stake them, since they are brittle, and must be protected from high winds. (If you've grown perennial Delphiniums, the plant size and growth is similar, but success with Dahlias is much easier.) Keep them free of bugs, well-watered, and well-fertilized as they grow, and your dahlias will begin to set buds by midsummer and be in full bloom, usually during July or August. Then the huge flowers keep coming until frost.
When frost threatens, just pull the roots up, cut off the stems, and store the tubers until the following spring. Each fall, you'll be amazed how the 'bulbs' have multiplied during the summer, giving you more and more to divide and enjoy the next year.
One expert has said, 'Never have so many gardeners received so much for so little work, as when they grow dahlias.''
First of all, Dahlias are great for cutting, as you can see in the large top photo of an arrangement showing a lavish deep red dahlia right next to a large, voluptuous rose.
Dahlias are native to Mexico, but there's about as much resemblance between the original and the Dutch hybrids as there is between an old toy car and a brand new Mercedes. Dahlias for today's gardeners offer a really big gardening treat.
The 'bulbs' are actually tubers, and look a lot like peony roots--sort of like a bunch of carrots. The plants grow quickly and some grow quite tall, always with lush deep green foliage.
Types of Dahlias. These plants have been hybridized into various heights from short bedding plants to tall bushy ones. But they are officially categorized by flower type or shape. The term, 'Dinnerplate Dahlia' is probably the most famous description, and though all gardeners use the term, it is not an official classification. 'Dinnerplates' are, simply put, the large plants with the huge flowers. The always-double flowers are up to 8', sometimes a whopping 10' across, so the name makes sense.
Photos A and C are examples of Dinnerplate Dahlias. As you can see, they come in both solids and bi-colors.
Photo B shows a whole border of tall dahlias in the garden.
Here are the official classifications:
'Decorative Dahlias' This group includes the Dinnerplates and also other taller (to 4 ft.) plants with double, chrysanthemum-like flowers. The famous 'Shogun Dahlias' are as tall as Decoratives, but have very heavy bloom of smaller bi-colored flowers for gardeners who want a large bushy plant covered with color.
'Cactus Dahlias' are the ones with the cactus-like blooms, often in super-bright bi-colors, always with the rolled, pointed petals. Like other groups, Cactus Dahlias can be of various heights, as long as they have 'cactus' flowers.
'Gallery Dahlias' are a newer group of shorter plants with flower-types of the Decoratives and Cactus groups. The Gallery group is named with terms from the art world including famous artists' names.
'Butterfly' or 'Impression Dahlias' are what the Dutch call 'bedding dahlias. They stay short, and are perfect for pots or borders. The names in this group all begin with 'F' like 'Futuro' and 'Fantastico'. The flowers are wide-open and daisy-like for a really colorful display of their brilliant hues. If well cared-for, watered, and dead-headed, they bloom constantly all season, making great masses of color.
There are other groups such as 'Ball Dahlias' and 'Pom Pom Dahlias' with spherical blooms, 'Colarette Dahlias' with uneven rows of petals creating a 'collar' effect--the varieties go on and on. Growing all of them is essentially the same, and best of all, it's easy.
Growing Dahlias: All the gardener needs to do is plant the tubers after spring frosts in good garden soil with full sun. It's best to position them against a wall or be ready to stake them, since they are brittle, and must be protected from high winds. (If you've grown perennial Delphiniums, the plant size and growth is similar, but success with Dahlias is much easier.) Keep them free of bugs, well-watered, and well-fertilized as they grow, and your dahlias will begin to set buds by midsummer and be in full bloom, usually during July or August. Then the huge flowers keep coming until frost.
When frost threatens, just pull the roots up, cut off the stems, and store the tubers until the following spring. Each fall, you'll be amazed how the 'bulbs' have multiplied during the summer, giving you more and more to divide and enjoy the next year.
One expert has said, 'Never have so many gardeners received so much for so little work, as when they grow dahlias.''
TIPS & GROWING INSTRUCTIONS: DAHLIA
Dahlias can be started indoors in individual pots with damp peat moss and vermiculite. You must use caution when transplanting them outdoors. Plant dahlias outdoors after all danger of frost has passed. Choose a sunny site with well-drained, sandy soil. Dig a hole a little larger than the 2” you’ll need to plant the Dahlia. Amend soil with peat moss or compost. Replace about half the soil, then place tubers flat and cover with remaining soil. Space tubers 12-36" apart depending on variety. Water after planting and not again until shoots appear. Stake plants. As plants grow increase watering. Fertilize sparingly. Pinch and disbud dahlias for later and larger flowers. Buds tend to grow in threes; two-sided ones should carefully be pinched to develop the central bloom. This is especially important with border or pot plant dahlias. If the plants are not pinched back, they will not retain their low compact size.
In areas with winter freeze, carefully dig the tubers in fall after the frost kills the foliage. Cut the stalk approximately 6" above the tuber. Dahlias should be dried for only a couple of hours before storing in plastic-lined shallow boxes with a blanket of vermiculite or peat moss. Hardy in Zones 8-10.