What a glorious month June is. After several chilly and wet weeks in April and May, the sun and warmth have arrived to get things growing vigorously. As you walk through your garden and admire its progress, pay close attention to what’s springing forth since now is the time to take action for even better blooms later on.
The late and learned horticulturist Fred McGourty of Hillside Gardens in Connecticut swore that the best tool we have is our thumb and forefinger. Others who might not like the inevitable staining of the underside of your thumbnail might opt for a pair of clippers or small pruners. If so, be sure to use a tool which is exceptionally sharp – your intent is to make a clean, swift cut, not to squeeze the life blood out of the plant. Bring along a spray bottle of a 70% alcohol solution, or a small container with the same contents, or disinfecting wipes to disinfect your pruners after each cut. You want to steer clear of spreading any disease from one plant to the next.
First, remove the spent flowers of all your spring bloomers: bulbs, irises and peonies. If you didn’t have any flowers this year, it could be too little sun, a need to be divided, food (or water in the case of Siberian irises), or recent transplanting. Inspect the plants now and note which ones need to be divided or moved in the fall. If you don’t have any of these plants, resolve to add them to your landscape this year. Irises and peonies come in a kaleidoscope of colors, are deer resistant, and add early color and delicious fragrance to your landscape. When finished, they leave a lasting green background for other summer plants. As perennials, they return each year, and are an effective camouflage when interplanted with spring bulbs to cover unsightly yellowing foliage. I’m hard pressed to find a reason for NOT planting irises and peonies.
Look over your sedums, mums, asters and Montauk daisies. Shear the top of each stem to encourage them to bush out. Here’s where your thumb and forefinger are superior to any clippers you may use – these are cramped spaces which most clippers can’t access without causing damage to the plant. If you want to minimize the staining mentioned earlier, scrape your fingers across a dry bar of soap first.
If you have later blooming balloon flowers (platycodon), tip them back as well to encourage branching down the stem. Don’t forget to pinch back tall garden phlox. If you lop off the front half of the plant by a third now, it will bloom in two cycles: back first (uncut) followed by the front. At that point, you can deadhead the spent blooms in the back for a better display.
Be aware that although pinching will encourage more branching, it usually delays flowering by about a week or two. After July 4, don’t pinch anything which hasn’t blossomed yet unless you’re not interested in flowers this year. If you can bear it, thin out your plants – like Shasta daisies and asters — which look overcrowded. You can simply oust stems which look thin and weak. Don’t take out more than 1/3 of the total stems of the plant. While you’re there, make sure to stake the plants to prevent them from falling over when they’re blooming.
Once the columbines and bleeding hearts have finished blooming, cut off the flower stems to encourage more leaves and a bushier plant. A side benefit is a plant that will provide more ground cover and less weed growth underneath. That trim will also prevent random seeding,
If you are fortunate to have lilacs, cut and shape your plants now. A reblooming lilac will be stimulated to produce another round of fresh flowers later in the season. Minimally, you will encourage new growth which will give you next year’s flowers. Also trim back rhododendrons and azaleas that have finished flowering.
If you notice your lilacs and tall phlox have a whitish cast on their leaves, you’ve probably got a case of powdery mildew.
Don’t fret – it won’t kill the plant. It’s a fungal disease caused by excessive moisture and poor air circulation – the plant can’t dry out quickly. First, remove and dispose of all the infected leaves and mulch surrounding the plant. Look around it to see if a neighboring plant is also affected and which neighboring plant can be moved to another place in the garden to improve air circulation. Powdery mildew is easily treatable with organic anti-fungal products available at your local garden center. Liberally spray this non-toxic solution thoroughly on the affected and neighboring plants, being sure to get to the undersides of all the leaves. You might have to repeat the treatment in seven to ten days, depending on the extent of the disease. The product label will give you all the info you need. If it isn’t killed, the fungus will lurk and reactivate with the next rainfall or wet condition. Therefore, it’s best not to water your plants from above or late in the day when they can’t dry off – switch to soaker hoses and early morning watering to prevent occurrence of fungal conditions.
In May, we had a hailstorm and several nights below freezing AFTER many perennials leafed out. Although they survived, they had significant damage. Andromeda and hosta are just two.
Your magnolia might have also been hit, since their flower buds are sensitive to cold temperatures, and are easily damaged by even light freezes.
Rest assured that your plants will recover after sustaining this damage. But you might want to cut off the unsightly foliage/flowers and stimulate the plant to regenerate new leaves.
The final thing you want to do this month is be sure your plants are well mulched. The dry months of July and August are ahead and well-mulched plants stand the best chance of surviving water stress. Coast of Maine has a range of mulches, including bark, cedar, and enriching mulch.
All can do the job of weed control and moisture retention while adding beauty to your garden for the entire season.
Written by Lorraine Ballato, author of Success With Hydrangeas, a Gardener’s Guide