No matter how grey the rain clouds are in June, patches of blue begin appearing in summer gardens as the bellflowers begin opening.
These vary from the low, creeping Fairies Thimbles (Campanula cochlearifolia) with its astonishingly large bells of blue, white or lilac to the one-metre white or purple-blue spires of the Batsin-the-Belfry (Campanula trachelium).
Campanuallas are an easy-tempered, usually perennial family, happy in sun or light shade and most soils-sometimes too happy. The Harebell (Campanula rotundifolia) repays good nutrition by running amuck in all directions.
But in poor, well-drained soil the Harebell roams less. It's also easy to hoe or pull out. Its large blue bells, each on its own wiry stem, are beautiful. Sometimes this plant is known as the Scots Bluebell.
A better-behaved plant is the Peach-leaved bellflower. This can be useful for containers since its large blue or white bells stand tall on a very narrow plant with an evergreen rosette of leaves at its base. It expands slowly but coexists well with other plants since it doesn't run. There are doubleflowered forms.
One of the longest-flowering campanulas (even longer with dead-heading) is the Carpathian Harebell (Campanula carpatica). This has strong, wiry clustered stems with a flower at the top of each. The forms Blue Clips and White Clips are often sold in garden centres. A dwarf, pink form is sometimes available. It's a nice, cut flower and not invasive, but it will self-sow.
Many of the campanulas have some drought-resistance, but Campanula poscharskyana is outstanding. It's a purple-flowered creeper that can handle more shade than other campanulas and is in flower from June to September -even longer if you give it a haircut.
It can be invasive, but I saw a lovely use of this characteristic in a Surrey garden in the dry shade of a big Douglas fir. Campanula poscharskyana was in full flower and beginning to climb up the trunk. Anything that runs along the ground will often try climbing as well.
Even more invasive, though also truly spectacular, is the Clustered Bellflower that produces purple flowers in a thick terminal cluster and all down the stem. In containers it needs solitary confinement. But in rural properties where people have large spaces to fill it can be quite useful. It's not for small lots with time-starved gardeners.
A much nicer runner is Fairies Thimbles (Campanula cochlearifolia). This is a 10 centimetre small-leaved beauty that delicately runs and flows over low rocks and around larger perennials then produces mats of big bellflowers just above ground level in late June.
The leaves vanish in winter, but are quick to reappear in spring. The really bad guy in the campanula family is the Creeping Bellflower (Campanula rapunculoides). This produces deep purple, narrow bellflowers along a great length of stem. The roots are fat, white and quickly plant themselves below the reach of most spades while the rest of the plant runs fast, smothering everything nearby while it showers seeds into the rest of the garden.
There is a vegetable campanula with a similar name: Campanula rapunculus. The root is said to taste like a walnut and apparently its young leaves can also be eaten. Its flowers are said to be white, pale blue or lilac.
Q: Some of the leaves on my Monarda didyma were darkening and curling inward with a white, frothy substance on the underside. Someone at a garden shop suggested spraying a mixture of soap, baking powder and water on the underside of the leaves. Now the leaves are spotting and curling. I had to remove some that practically fell off. The plant looks unhealthy. It used to be the most robust in my container garden.
A: The white frothy substance is a foam that protects a little larvae inside called a spitbug. Though unsightly, spitbugs don't hurt plants. But if they bother you, remove them from the leaves. Or pick off the leaves.
I think the garden centre person misunderstood your problem and gave you an organic recipe for powdery mildew. Monarda is prone to this, but powdery mildew is definitely not frothy. It's powdery. The curling and drying is most likely caused by lack of moisture. Monarda is a mint family member and does best in moist soil.
Containers are notorious for drying out when temperatures rise into the early 20 C and in those temperatures, it's best to water containers twice a day, especially if they contain moisture-loving plants.
Some people combine moisture-loving and drought-loving plants in the same container. This makes watering challenging.
I should add, that if your monarda is dry at the roots for several weeks, this could trigger a real attack of powdery mildew.
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