A grandma living down a few houses in our street is from Eastern Europe and, though she is in Canada for a long time, doesn’t speak English well. That didn’t stop my wife from striking a conversation with her. Somehow both understand each other very well, which wonders me.
But my wife’s complain is that as soon as she asks for dahlia tubers, grandma starts pretending not to know English.
Well, grandma is having a carnival of dahlias through all summer.
And doesn’t want any competition next door!
That’s all she grows, besides a few roses.
For me, dahlia is too much work.
I am a plant-one-time-and-forget guy.
So more perennials and a few annuals.
I am not into digging every fall to store tubers in ‘cool and dry place’!
Whatever that may be!
My shallots and garlic always become dead dry in my basement.
In my wife’s insistence, I planted a few and saved the tubers in peat moss to see them… what else? Dead dry!
But dahlias are a must-have, if you are into exhibitionism.
Even if you are not, they will do that for you!
These flamboyant flowers come in a rainbow range of colors and sizes from 2 to 10 inches. They grow around 5 ft tall and need stakes to stand up.
Dahlias (Dahlia pinnata) are natives to Central Mexico and bred to have so many varieties.
As they are from Mexico, they are tender perennials.
In extremely hot and humid areas they are hard to thrive, but well suited for cool, moist climates.
They are hardy to zone 8. Those in those areas can cut back and leave them with dry mulch to overwinter.
Come spring, they will shoot back.
In colder climates with frost, they are treated annuals, unless you store those tubers in that proverbial ‘cool, dry place’.
If you don’t want to bother with digging and storage, treat them like annuals and plant them annually.
How to propagate dahlias
You can grow them from seeds or tubers. (store-bought or lifted from grandmas next door!)
Grow from tubers
Early spring, you can get them at big box stores, imported from, where else, The Netherlands.
A place where bulbs and tubers are bred and grown for exports.
Wrinkled or rotten tubers should be avoided. Having some green growth means they are healthy. Even though they are tubers like potatoes, don’t bother cutting them to save money.
Grow from seeds
You can grow them from seeds. ( claimed from grandmas!)
But they aren’t going to true to their mothers. With cross-pollination, you might get something completely different… hybrids.
Hey, this is how breeders get their varieties.
So you can sow directly outdoors or start indoors. With a good base seed-starting mix, plant seed half inch deep, making the mix moist and cover with polythene to keep humidity.
Leave at warmer place, away from direct sunlight.
Seeds will germinate about in a week.
Grow from cuttings
You can also root the cuttings.
Remove main shoots with a bit of tuber at the bottom.
Take out the leaves, except the two top ones. Put them in pots, spacing to avoid touching each other.
Water them and cover them with polythene with supports that prevents polythene from touching the stems and seal with rubber band.
Put them in warm place, away from direct sunlight. Direct sunlight might burn them.
In 3-4 weeks they will root. Plant them outside in spring.
How to plant dahlias
As they don’t like cold soil, wait until the last day of frost in spring. So plant them when you plant tomatoes and peppers.
You can start them early indoors to get a head start and have flowers early.
In March or early April, put them in pots filled with potting soil. Keep the soil moist and place them indoors.
By the time of last frost date, you will have a healthy plant that is ready to be planted outdoors.
Growing dahlias in containers
If you don’t have space or want to have flowers for cutting, you can grow them in containers.
In containers they don’t have to compete with others for nutrients and water.
Choose bigger containers in size about a feet in width and height for optimal growth. Use good soil mix containing compost and manure for strong growth.
Plant the tubers deep as in ground, cover with some soil. As the sprout emerges, you can add more soil gradually.
What dahlias need
Dahlias need sunshine, a lot of it, about 6-8 hours.
And their stems are brittle, so they don’t like wind. They break easily.
So choose location accordingly.
Direct sunlight and away from direct wind.
As usual, nutrient-rich soil with good drainage is needed for them to thrive.
According to their flower size give them space, from 1-3 ft.
Plant the whole tubers horizontally around 6-8 inches deep, with growing sprouts facing up with crowns just above the soil level.
But don’t water them when you plant. This will encourage rot. So wait until see some growth.
As long as you plant them in moist soil, you should be fine.
Also, don’t cover them with mulch.
Give dahlias enough support
Large flowered dahlias need support. So use stakes or cages when planting tubers, so you can train them as they grow.
But use flexible ties, not rigid ones that damages the stems when they become bigger.
Or tighten loosely to allow growth.
Make sure you put stakes when planting.
Why? You might damage tubers underground.
Once they grow to their full size, the growth hides the stakes easily.
Encouraging vigorous growth
When they start growing, you will have lots of sprouts coming off the crown. You shouldn’t let all of them grow as they will compete for nutrients.
With a sharp knife or fingers remove sprouts, leaving 4-6 sprouts only.
This will encourage bushy and vigorous growth, resulting lot of big flowers.
They will start flowering after 8 weeks, in mid-July.
Taking care of dahlia plants
Once you see the growth, start watering to get the soil wet enough. As they are succulent, they need more water.
Always keep soil moist, but do not let the water stay.
Water blocks air to the tubers, leading to rot.
They don’t mind low-nitrogen fertilizer. But don’t over-fertilize. You will see more green growth and less flowers and weak tubers, sometimes, rot.
Large flowers fill up with water after rain or sprinkling and bend and break their heads.
So pay attention to it.
Dahlias set buds with one large bud at the tip and smaller ones around. If you remove smaller ones (lateral buds), one at the tip (terminal bud) will grow to be a big flower.
If you want bigger flowers for cutting, competitions or shows, remove the lateral ones to get big flowers.
Keep cutting flowers more to encourage more new flowers. Remove dead flowers.
Eventually, with first frost, plants die.
Pests and diseases
Slugs and snails feast on their growth.
There are problems with mites and aphids. Also with powdery mildew in fall.
Earwigs and cucumber beetles eat the petals.
For those with wildlife, deer is another headache.
Cut the foliage to 2-4 inches above ground and dig the tubers.
Be careful not to damage tubers when digging.
Use garden fork to dig away around a feet from the center and lift the clump carefully off the ground without damaging new sprouts.
Remove the rotten tubers from the clump and let them air-dry.
Pack in loose material like vermiculite, foam peanuts, sawdust, peat moss.
Store them in paper bags for breathing, inside cardboard or wooden boxes.
Don’t use plastic bags or bins. You want good air flow.
Store them in well ventilated place indoors.
Check them often for shriveling and rot.
If shriveled, moisten the storage medium. Remove the rot ones.
This is how you rinse and repeat dahlias.
It all looks like hard work. But once you see the flowers showing off like showgirls, you will have your own carnival.
Like roses and hostas, once you are hooked, you will start collecting them to the point of addiction.
But remember to share those tubers with your neighbors.
But if you want to claim tubers from your neighbo rs, be aware of the hidden cameras and YouTube Stardom!