Dahlias, Easy to Grow

Dahlia

Dahlias are one of my favourite flowers to cut for a vase in the house.  Partially because there are so many blooms on one plant that you hardly miss them when you cut a few and partially because they last so long in the house.  The other reason is that they are delightful.  Each flower is a perfectly formed wonder, petals attached to more petals attached to more petals, forming a wonderful; almost kaleidoscopic (is that a word?) arrangement within each flower.

There are so many varieties to choose from. There are the popular dinner plate dahlias which offer the largest flower, thus the name, right down to the patio dahlias, short and compact and perfect for containers.  Pom Poms are little wonders on long stems, cactus varieties have more pointed petals and collarettes are a pretty choice.  Available in wonderful sunset colours, soft pastels, cool whites, vibrant reds, purples, striped, mottled, you name it.

Dahlias are easy to grow.  They arrive in the garden centre as a cluster of fleshy fingers and toes (well, that’s kind of what they look like) called tubers.  All these appendages are attached to a neck which is actually the dried stem from last year’s plant.  Dahlias can be planted in the ground after the chance of frost is over or potted straight into a container to enjoy on the deck.  Full sun is preferred although they will bloom fairly well with some shade.  Well drained soil is a must otherwise the tubers will rot, especially if you plan on leaving them in the ground over winter.

Dig a planting hole about 6 to 10 inches deep and wide enough to accommodate the tuber. Amend with Sea Soil, a handful of bone meal and some compost if you have it.   Place the tuber in the hole, neck pointing up and gently spread out the fingers and toes (this isn’t the correct terminology, by the way).  Since most dahlia varieties can get quite tall and need staking now is a good time to put some kind of support into the ground next to the tuber.  Tomato cages work well, also, for the shorter varieties.  Cover up the tuber with soil and water well.

Dahlias enjoy an all purpose fertilizer during their growing period like GardenPro, my favourite is Perennial and Vine, and deadheading spent flowers is a must to encourage more throughout the season.   They also like a fair amount of water but don’t like water-logged soil.

One pesky problem with Dahlias is that earwigs also enjoy their flowers.  There isn’t a lot you can do about this other than setting up earwig friendly houses and disposing of them regularly to keep the numbers under control.  An overturned pot stuffed with newspaper is one way of catching them.   Diatomaceous Earth is another fairly effective solution at keeping the ugly critters at bay. It is a mined product and consists of tiny fossilized diatom remains. It works by sticking to the exoskeleton of the earwig and abrades it as it moves around resulting in holes which lead to dehydration and death.  Not a pleasant thing so if you can put up with a few deformed flowers then don’t worry about it as earwigs eat aphids which is a good thing.

I leave my dahlias in the ground all year round and they come back fine pretty much every year.  Once in awhile I’ll lose them to an exceptionally cold winter but that’s just an excuse to try another variety.  If you want you can dig them up after the frost has blackened the leaves, brush off the soil and store them in a cool, dry place.  Or after a few years dig the tubers up and divide them as they don’t really like to get too crowded.

Blooming mid summer to first frost, dahlias of all shapes and sizes are a gem to have in the garden and I highly recommend them.  As someone who doesn’t generally like to cut her flowers for a vase I love having a few dahlia plants around.  Their perfect forms are a treat to have in the house to enjoy when you can’t be outside.

Shirley Eppler

March 2010