Question: I’m uncertain when and how to prune my clematis. Can you give me some guidelines?

Answer: Clematis are hardy vines with spectacular, showy flowers that can add pizzaz to any garden. Though they prefer a higher soil pH, they can share space among rhododendrons and azaleas in acidic soils. Most importantly, they require a rich organic, well-drained soil.

The objectives in pruning clematis are to maximize flowering and manage the size of the vine. But first of all, you need to know what type of clematis you have, which is determined by when the particular cultivar flowers.

Clematis varieties fall into three different groups. In Group 1 are the early flowering species that bloom on old growth—flowering from March to June. Some popular varieties are C. armandii, C. Montana and C. alpina. These can be pruned right after flowering, if at all, pruning back weak and tangled stems.

Group 2 clematis bloom from April to June and sometimes provide a second bloom in September. Flower buds grow on new and old wood, so only do some light pruning in early spring before they begin to grow, only pruning off any deadwood. These are the large-flowered species like “Nelly Moser” and “Dr. Ruppel.”

Group 3 clematis bloom later in the season, from July until first frost, blooming on the current year’s growth. Varieties like “Ernest Markham” and “Jackmanii” should be pruned back hard each year in late winter, 12-24” from the soil line, leaving at least two pairs of buds on each stem. Many of these plants can add up to 8 feet or more of growth in one season!

By observing your clematis, and the timing of its blooming during the season, you can readily determine which group it falls into in case you lost the label and don’t know what variety it is.

By planting clematis varieties from different pruning groups, you can have clematis blooms in your garden from spring till frost, and there are thousands of different colors, sizes and shapes to choose from. Clematis are very resilient plants, so take heart—you’re unlikely to kill it by making a pruning mistake. Remember: If in doubt, don’t prune before flowering.

Question: What are some ways I can put my used coffee grounds to use in my garden?

Answer: Used coffee grounds can be a wonderful addition to your garden as a mulch and in your compost pile. Something to note about used coffee grounds: they are not acidic as may be supposed but are closer to a neutral pH, so they can be spread under roses as well as blueberries. The acid in the coffee beans is mostly water-soluble, so it leaches into the brewed coffee instead.

Since used coffee grounds are about 2 percent nitrogen by volume, they can be a safe substitute for nitrogen-rich manure in compost. As grounds decompose, they appear to suppress some fungal rots and wilts, but only small amounts are required for disease suppression.

Earthworms and red wigglers enjoy a good meal of coffee grounds, pulling them deep into the soil, resulting in improvements in soil structure. The addition of coffee grounds to make up 25 percent of the volume in your compost pile helps sustain high temperatures, which reduce potentially dangerous pathogens as well as killing weed seeds.

As a mulch, spread used coffee grounds on the soil and cover with leaves, compost or bark mulch. Always cultivate the grounds into the soil first so they don’t dry out, or they will repel water in much the same way as peat moss when it becomes dry.

Also, it’s good to add a nitrogen fertilizer at the same time you incorporate the grounds directly into the soil. Coffee grounds encourage the growth of microorganisms in the soil, which use nitrogen for their growth and reproduction. Thus, adding additional nitrogen fertilizer provides a source of nutrients for your plants.

So save up those used grounds after your morning cup of Joe. You can store used grounds in a container as they don’t go “bad,” then when it’s full, add to your landscape or compost pile. Some local coffee shops are glad to off-load their spent grounds if you’re wanting a larger quantity. Make sure to make prior arrangements with them and provide a labeled, clean 5-gallon bucket to put them in.

Do you have a gardening question? Please e-mail, call or visit the Douglas County Master Gardener Plant Clinic at, 541-672-4461 or 1134 S.E. Douglas Ave., Roseburg.

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