If you can live with just a bit more work in the garden than is required for more run-of-the-mill plants, try planting a Dahlia or two this spring.  You won't be disappointed, and your will definitely draw rave reviews from visitors!

Of all the choices in flowering plants that the home gardener can make, Dahlia is certainly one of the most versatile.  The sheer range of color and form is almost endless, with vivid solid colors of almost every hue and endlessly fascinating bicolors ranging in sizes from tiny pompoms  to huge plate-sized giants. Admittedly, Dahlias require a bit more work than, say Daffodils or Marigolds, but carefully chosen varieties will add more to the garden space than just about any other choice in plants.  Blooming from midsummer until well into the fall, Dahlias put on their show right about the time when most gardens are starting to fade from the heat - a welcome garden addition indeed!

The downside to growing Dahlias is the extra work involved in making sure they thrive in their place in the garden.  Dahlias put out tubers that look something like sweet potatoes, and will absolutely not do well in soil that stays wet or soggy.  They are not terribly particular about the soil otherwise, but as with most plants, the better the soil, the better the outcome.  They are somewhat shallow-rooted plants, usually with flowers that are quite heavy, and as such almost all larger varieties need staking to keep the flower heads up and prevent the plant itself from blowing over in the wind.  They like the sun and will become leggy with few blooms in heavily shaded areas.  A minimum of 5 hours of sun or slightly dappled shade in hotter climates will produce the best specimens, with 8 hours ideal in cooler climates.  Many Dahlia experts also recommend pinching the larger varieties to encourage branching and to force bigger flowers.  Lastly, in all but the warmest climates, Dahlias need to be dug in the fall and carefully stored for use the next year.  That right there is enough to discourage many gardeners, including me (I just grew my very first Dahlia last year and it's still out there) but there may be ways around that in all but the coldest regions (more on that and on pinching later in this discussion). 

So now that you have decided to try growing Dahlias despite the pitfalls, where do you start?  The fun part, of course - picking out what you want to see growing in your garden!  Dahlias can be grown from seed, tuber, or cutting.  Obviously, seed is the cheapest, and if you are good at seed starting this is the way to go.  I priced tubers for 2007 online, and they run about $4 to $5 apiece compared to $2.50 or so for a seed packet with 50 seeds.  Large varieties grow 3-4 feet tall on average and require stout staking (3 rods in a triangle or a tomato cage at planting time).  Medium varieties grow 1-2 feet tall and also require staking, but one stake at planting time should do it.  Small dahlias grow 10-20 inches and usually don't require much in the way of staking at all.  Do yourself a favor and try at least one big Dahlia this year just for for fun - guaranteed it will be a memorable gardening experience!

Dahlias start readily from seed, but the soil has to be warm or the seeds will not germinate.  Start indoors a few weeks before the last frost date in your area for an earlier show.  Use a good seed starting medium, spread the seeds, and top off with a thin layer of more of the seed starting medium.  Spray or water from below, and set the seed tray in a warm place out of direct sunlight.  The top of the refrigerator is a good choice.  Cover the seed tray with plastic wrap to hold the moisture, if desired.  Seeds should sprout in 7-10 days, but give them time - they don't sprout all in the same day generally.  Once the seedlings are about 3 inches tall, move them to small pots and place in a sunny windowsill.  When the danger of frost is completely over and the soil has warmed, transplant to the garden.  Don't jump the gun on this one - the soil HAS to be warm or the plants will not do well.  Plant about an inch deeper than they were in the pot. 

To plant tubers, dig a hole about 10 inches deep and then backfill to about 3 times the tuber diameter. Place whatever you have decided to use for stakes at this time, and then place the tuber flat with the eye pointing up and fill in the hole.  Do not water at this time - wait until you see the first growth before applying any water, and then through the season, take care to give the plants at least 1 inch of water per week to keep the soil moist but not soggy. Space the plants according to their mature size - this could be anywhere from 12 to 36 inches.  Fertilize monthly using a low nitrogen fertilizer such as 5-10-10 for better blooms, but stop fertilizing completely in August. 

To help your Dahlia plant become more bushy with bigger blooms and better stems, pinching is a good practice.  Once the plant is about a foot tall and has 3-4 sets of true leaves, pinch out the middle shoots to encourage branching.  Dahlias bud in threes at the end of each branch.  For dramatically bigger (but fewer) blooms, pinch out the two side flower buds when they are about the size of a pea, leaving the middle bud intact. Of course, pinching and disbudding is not an absolute requirement for Dahlias, and if you choose to just let mother nature take her course, you will likely still have a nice plant with beautiful blooms. 

Dahlias make excellent cut flowers with a vase life of 1-2 weeks.  Flowers should be fully open before cutting, as Dahlias do not continue to open once the flower is cut.  Cut the flower during a cool part of the day - early morning is ideal.  Use a sharp knife and be careful not to crush the stem.  Place the flower in a few inches of hot water for an hour or two to prolong bloom life, and then arrange as desired in the vase. 

If you are a balcony gardener or don't have a garden area, Dahlias are an excellent choice for container gardening.  Choose a container roomy enough to accommodate the tuber with a little room to spare on the sides and deep enough to plant the tuber at least 6 inches deep.  Don't fill the pot completely up with soil after planting the tuber - instead add soil as the growing season goes on to help stabilize the plant.  Stake as necessary, depending on size of the plant.  During the growing season, water every few days, taking care that the soil is moist at all times, but not soggy.   

At the end of the season, if you plan to dig your Dahlia tubers, wait until the first frost blackens the leaves, and then cut the plant down, leaving about 4 inches of stem.  Remove stakes and ties that might interfere with the digging process. Using a spade or garden fork, start about a foot from the stem, and gently dig around the plant until it loosens up, then gently remove it, being careful not to break the stem.  Once it has been removed, gently clean the tuber using a garden hose and let it dry thoroughly, being careful not to let it sit exposed for too long or it will begin to shrivel.  Using a pen with indelible ink, write the identification data for the type of Dahlia right on the tuber.  To store the tuber, choose a suitable material such as sphagnum moss,  sawdust, wood shavings, or vermiculite and bury the tuber in that material either in ventilated refrigerator bags or in boxes.  If using clear bags, the tubers must also be boxed to prevent light from reaching the tubers.  Store somewhere with a temperature not below about 35 degrees and not above about 50 degrees.  A garage, crawl space, or outdoor shed will work nicely. 

For those in more temperate climates (zone 6 or 7 and up), it may not be necessary to dig your Dahlia tubers every year.  I know people in my zone 7 area that use heavy mulch in their Dahlia beds and the plants come back year after year, only requiring digging occasionally to divide the tubers for more plants.  Freezing will kill the tubers, but if your garden has well-drained soil and a south-facing and hopefully somewhat sheltered orientation, it's very possible that you may be able to pull the tubers through the winter with no damage if you apply a suitable amount of mulch material. 

As far as pests and diseases, Dahlias have their share of problems.  Slugs and snails will travel long distances to attack a young Dahlia shoot, so prepare to do battle with them right out of the gate.  Once the plant matures, it is not such a target, but watch out for this in the beginning of the growing season.  Other pests that Dahlias are susceptible to are earwigs, aphids, thrips, caterpillars, and tarnished plant bugs.  Use a general insecticide to battle these pests if the situation warrants it.  Fungal and virus diseases are common in Dahlias, and proper spacing so that the plants get adequate ventilation will circumvent many potential problems. Occasionally, a plant will become infected with a viral disease, and in those cases, the plant should be removed and disposed of as quickly as possible. 

Lastly, Dahlia tubers are edible, but there is some question as to what they actually taste like, although by all accounts they don't taste very good.  I'll let you know when I buy some for this year's garden!

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