Q: When should I prune my Lilac?
A: Flowering shrubs should be pruned just after they have finished flowering. With the lilac that would be in early summer, late June or early July. Lilacs buds are formed during the summer and need winter frost to mature, so Fall pruning will remove the flower buds for next year.
Q: How should clematis be planted?
A: Plant clematis in the Spring in moist, not wet, loamy soil with good drainage. Clematis does best when its roots are kept cool so a mulch after planting is a good idea. Shade from the hot afternoon sun is also helpful.
Q: Why has my two year old wisteria never flowered?
A: Some wisteria do not bloom until they are 4 to 6 years old. So it may be too young. Wisteria prefers mildly alkaline soil and will bloom better if it is not given too much nitrogen. Nitrogen promotes leaf growth perhaps at the expense of flower production. If after a few years it still does not flower, prune the roots by digging straight down into the soil about 18"/30cm. from the trunk.
Q: When is a good time to prune roses?
A: Roses should be pruned in their dormant period, between leaf drop in the Fall and bud break in the Spring. In our climate roses will die back during the winter leaving a line of demarcation between the green living base and the black dead part of the branch. The pruning cut should be at that level. Fall pruning can be used to lower the plant form to avoid breaking of large branches from the weight of winter snow. Spring pruning can then be as above. Do not prune in the winter. Be sure your pruners are clean and sharp.
Q: What are some good vines to cover an ugly garden fence?
A: There are several that would do well. Wisteria is one. Clematis including the showy jackmanii makes for colorful flowers throughout the Summer. Trumpet vine (Campsis radicans) grows well in this area. It can be invasive and so needs to be well pruned. Climbing Honeysuckle (Lonicera henryi) for example also works well. Virginia Creeper ( parthenosis cinquefolia) and Boston Ivy (Parthenosis tricuspidata) are easy to care for. Their flowers are small and undistinguished, but their leaves flame into a brilliant Fall display.