Good gardeners approach their craft scientifically, create the right soil, place the plants knowledgeably, fertilize carefully, train and prune properly.
Then Mother Nature takes over and has her way.
I have never understood the peculiar combination of sun and water and temperature that makes some years great for some plants, other years terrible. Nevertheless, beset by a poor year, I’ll offer up the unusual growing conditions of that season (and every season has something unusual) as an excuse. And when conditions are on the nose and the garden bountiful, I credit my skill.
This summer, I have been especially skillful with dahlias. Normally the queen of the fall garden, this year it’s an empress, with large, luscious flowers covering seven-foot plants and new buds lined up to keep them in abundant bloom, no matter how much I cut bouquets, until heavy frost shuts them down.
Dahlias are easy enough for the beginner to be successful. In spring plant the tuber an inch or two deep in decent soil and full sun. They’ll take half day exposure, but the more sun, the more flowers.
Though they’ll grow in normal garden soil, a little effort pays off extravagantly. They love rich soil with lots of compost and supplemented every few weeks with a liquid 15-30-15 fertilizer.
Dahlias are usually purchased in spring, when boxes with enticing pictures fill the big box stores, and some may still have a few left at half price. Don’t be seduced into buying them. The pictures may still be fresh, but the tubers are not, after the summer growing season is spent in a plastic bag.
Nevertheless, this is the time to shop for the very best bargains in dahlias, and here’s how you do it. Visit a friend’s garden and say (you should practice this at home), “My, what a beautiful dahlia. Where did you buy that? I’d like to buy one for my garden.” Your friend will almost certainly offer to give you a tuber as soon as the season ends.
This works for three reasons. First, because no one ever takes my advice to put the plant’s source on the label in the ground, if they label them at all, so your friend probably has no idea where it came from.
Second, dahlias multiply. A single root planted in spring results in a clump several times the size in fall. It doesn’t take long to run out of space to grow them. Or store them.
Third, dahlia tubers aren’t hardy. They have to be dug up in fall after hard frost kills the tops and stored over the winter. Since there won’t be enough space to plant all of them next spring, most gardeners think, “better you store them than me.” So you shouldn’t be hesitant to hint broadly.
Maybe that friend is one of those gardeners who treat dahlias as annuals and just let them die in the ground over winter. Maybe even you are one of those. Sad. What kind of gardener doesn’t love an easy, sweat-free job on a sunny, crisp day in fall. It’s really simple. After hard frost completely kills the top growth, wait a few days until it collapses. Then cut if off, leaving six-inch stubs. Lift the clump with a spading fork. Big, isn’t it? Shake it to knock off the bulk of the soil; it’s not necessary to get it all off.
The tuber clump needs two or three days to dry. Place them upside down (that’s important) in a sunny spot in warmish temperatures, if you can arrange for the right weather. Otherwise take them inside or into the garage. If you have an old house with a cool, damp basement, just throw them in a box. In a newer house with a tiled furnace room, it is better to store them in a plastic grocery bag with some wood shavings or kennel bedding for packing material. The books say use peat moss. Don’t.
Another problem with a furnace room or anyplace in the habitable part of the house is temperature. You want it as cool as possible; in warm temperatures they will sprout too early in spring. If you don’t have a cool spot inside, an attached garage that doesn’t drop below freezing works fine. If you think it might get too cold at night, put them in the picnic cooler; you won’t need it much for a while anyway.
Now head over for the similarly impaired friend who has the dahlia you covet and show them how to do it. It isn’t necessary to divide your clump until next spring unless you want to break some off to trade.
Besides price, there are other reasons to shop this way. You get to see the plant in full bloom instead of trusting the package description. You get to see the real color instead of the sometimes unreliable pictures.
For some reason, the people who write the package copy think all dahlias grow to 48 inches. Every package says the same thing; I’m pretty sure the blurb writers have never grown a dahlia. In my experience, most four-foot dahlias are six or seven feet tall. That means that, for best results, they should be staked. Traditionally this was done by pounding a tall stick in the ground at planting time and tying it up every few days, but I’ve found it much easier to use tomato cages, especially the greatest cages of all, ones you make from concrete reinforcing wire. Or you can just let it sprawl, in which case it might actually be four feet tall.
Concrete reinforcing is heavy wire woven, welded actually, into a grid with six-inch squares. It comes in sheets of various sizes, but I prefer the kind that comes in five-foot-wide rolls. Cut off six squares (bolt cutters work best), leaving naked prongs at one end. Form it into a cylinder and fasten it with the prongs. It is the best support for tall plants and lasts forever. There are some in my garden that have been there for 30 years or more.
One thing the package rarely tells you but you can check in your friend’s garden is the stem length. Since dahlias are so perfect to cut and bring indoors, you want long stems. Otherwise you have these huge dinnerplate flowers shlumping with their chins on the rim of the vase like sullen teens at the dinner table.
If you must actually purchase dahlias in spring, don’t get the cheap mixed bag. This is a lesson I have learned often but never very well. So if anyone wants some really ugly dahlias, a whole row, all in the same muddy rose and cream color, drop by my garden in November. Bring a big bag.