Middle to late May is blooming with colors, and now is the time to feed and weed. The roses, perennials and newly planted annuals are all putting on their growth spurts and looking for food. Think slow but steady when it comes to fertilizing. Improving the soil with compost and organic mulching is about all the fertilizing that most trees and shrubs will need, but hard-working, heavy-blooming plants such as roses, daylilies, iris, clematis, and bedding plants like geraniums, marigolds and petunias need more food.
A slow-release fertilizer such as Osmocote or Dymamite or an all-organic mix of fish fertilizer releases nutrients into the soil gradually as the temperature rises. These also are the fertilizers that only need to be applied once each growing season.
Plants in pots, especially hanging baskets and containers of blooming annuals, will show off better blooms when given an additional shot of water-soluble plant food like Miracle-grow, or Peter’s professional plant food. This is because not only do these heavy duty plant foods have every nutrient your plants could possibly need, but when fertilizers are dissolved in water they get to the roots and get sucked up immediately – very important when summers are cool and growing seasons are short.
Fertilizing plants with organic fertilizers such as manure teas, compost teas, alfalfa pellets and homemade compost provides food for soil organisms and improves the tilth or structure of the soil as they release smaller amounts of nutrients more slowly over time. If you’ve been improving your soil for years your vegetables and flowers may produce beautiful results with only organic amendments. This should be the goal of every gardener.
Meanwhile, supplement your buffet of plant nutrients this month by fertilizing everything in pots and all your heavy bloomers. May is the lusty month of luscious plant growth, so let the feasting begin!
Tips for growing clematis
Traveling all the way from the English Channel and the isle of Guernsey, Raymond Evison is the king of the clematis. He also is the father of the compact container clematis. After giving a lecture at a local nursery (Molbak’s in Woodinville) he agreed in an interview that there were several reasons why his compact clematis vines have become blooming best sellers this spring.
1. Container gardening is growing in popularity as yards become smaller and more people garden on balconies and in condo-size gardens.
2. The more compact container clematis flowers on new growth, so you grow a clematis vine covered with blossoms from the bottom of the vine to the very top.
3. The long bloom time that has been bred into these tidy little vines means you get months of flowers from just one plant with a shorter dormant or resting time. (In my garden a Raymond Evison clematis called Cézanne flowers from May until October without stopping!)
So what advice does this proper gentleman with the British accent and lifetime of plant exploring, plant breeding and plant growing offer to American gardeners?
Tip No. 1: When it comes to pruning, don’t worry – do the pony-tail cut.
The more compact container clematis like the blue Cézanne, deep red Picardy and pure white Arctic Queen, all can be tamed with what Mr. Evison calls the
pony-tail cut. In late April, grab all the stems of your clematis in one hand and cut them off all at one time to within 4 to 6 inches from soil level. Harsh discipline to be sure, but this forces the awakening vines to produce a rush of new spring growth and you’ll encourage flowering from buds that emerge the entire length of the vine.
I admit I have not followed this advice myself. Instead I carefully prune about one-third of the stems on my Cézanne clematis to the ground, shorten another third by one-half and the last third I leave rather tall. I don’t want to wait for June blooms and leaving part of the vine unpruned means I already have flower buds opening in May.
Tip No. 2: Get creative with these climbers.
Evison showed clematis growing up rose plants, clematis clinging onto chains to form-flowering garlands, clematis covering apple trees, garden sheds and intertwined into evergreen hedges. One combination I had never tried was clematis and heather. Clematis make great blooming groundcovers and low-growing heathers provide a beautiful carpet for these sprawling vines.
Tip No. 3: Get supportive after a storm.
Look for windfall branches from birch trees or other finely branched boughs and use these natural branches as supports for your potted clematis. Placing three skinny tree branches into a large container, teepee style, will provide a cone-shaped frame for your potted clematis to strut its stuff.
Growing tips: Use a pot with thick walls for growing clematis, the better to protect the roots from heat and cold. Evison does not recommend plastic pots. Add organic matter like compost to the potting soil but make sure there are plenty of drainage holes in the bottom of the pot. Choose a pot at least 12 inches deep. When planting a new clematis place it 2 to 3 inches deeper than it was growing before. This will encourage the vine to make extra surface roots for a stronger plant.
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