I became a master gardener through the OSU extension program here in Oregon primarily to share my passion and knowledge about dahlias. I grow about 75 varieties, many rare and harder to find, and I sell tubers in the spring. Some may not even know what a tuber looks like or how to identify the parts, so please take a look at this first image and familiarize yourself with the three main parts of a tuber; the body of the tuber, the neck, and finally the crown -- where the sprouts or "shoot" will come from in spring. The "eyes" are the beginning of sprouts and the "tail" is just where the roots grow from to nourish the tuber and the resulting plant.
Orange dahlia pictured above: Bloomquist Jean
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| photo credit: theseedcollection.com.au |
Dahlia's can be nitpicky, they like moderate growing temperatures in the summer (anything over 75 and they get a little weak in the stems and may require shade and extra watering) and the tubers will die if they are subjected to freezing temperatures during fall or winter. To top it off, too much rain in the spring can rot the tubers, so it's best to dig them up in the fall after blooming and store them, or if you have mild winters, cover the ground with plastic to protect from too much rainfall.
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| Thomas Edison, Clearview Debby, Diva, Ferncliff Inspiration |
These beautiful flowers come in all shapes and sizes, this is due to the fact that dahlias are octoploids, meaning they have 8 sets of chromosomes and a comparably large genetic variance. They can be pink, red, yellow, white, purple, and any shade in between. Dahlia's do not come in green or blue, but the amazing array of colors, and the amount of colors within one flower, will astound you. The American Dahlia Association recognizes many different dahlia forms, or shapes, as well, and that number currently holds at 20, with formal decorative, stellar, and informal decorative being amongst the most popular.
When should you plant your tubers? Well, it depends on your zone, your last frost date, and how much rainfall you get annually. I live in zone 8b, coastal Oregon, and I plant late May, though I often start my dahlias indoors under grow lights in small pots so that I can get a head start and earlier blooms. Some people in California plant as early as April, but it all depends on your weather. Dahlias don't grow well in soil that isn't 55 degrees or above, and they will freeze and rot if subjected to anything below freezing, so make sure that you are well past your last frost before sticking any tubers in the ground. If you live in a milder climate like I do, you can over-winter your dahlias in the ground and they will start that much sooner in the spring -- my first blooms are always from over-wintered varieties.
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| Dwarf landscape dahlias, Tabasco and Hypnotica |
What happens after you plant your tubers and they come up? Well, you do a happy dance of course, and then you wait until your plants have five sets of leaves (including the very first set of proto-leaves) and then you pinch off the top bit of growth so they will branch and you will get bushier plants and more blooms. Congratulations, you're a dahlia grower now! Don't forget to dead-head your blooms and cut deep when collecting for bouquets, this will encourage longer stems and more growth and will signal to the plant that it needs to keep making more flowers. Have fun, and water deeply at the base of the plant (to avoid mildew developing on the leaves) at least once a week — and more often in hotter climates.
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| HollyHill Lemon Ice |
