I stored cannas over the winter in an aluminum tin filled with peat moss. How do I know it they survived the storage OK? What should I look for? When and how should I replant them in the garden?

Cannas are generally easy plants to carry over as long as the tubers are not allowed to freeze and they do not dry out excessively. The ideal storage temperature is in the 50 to 60 degree range. Canna tubers stored in an unheated garage will freeze and be literally mush by spring. On the other hand, cannas stored in a hot closet in a paper bag become shriveled, dehydrated lumps by spring. This does not have to be the case!

To properly store cannas:  Lift the cannas in the fall just before or right after the first light frost. Leave the tuber clumps together even if they have become large. Rinse off the excess soil from the tubers. Allow the foliage to dry, then detach the stems from the tubers. Store the tubers in sphagnum peat or vermiculite in a container that “breathes,” like a cardboard box (not plastic!). The trick here is to minimize air movement around the tuber.

If you’ve done it right, your tubers will be firm, yet plump. They should not be moldy or have a slimy coating. New shoots, or “eyes,” may be evident as tiny points on the tuber. Tubers may be divided prior to planting—maintain at least 2 to 3 eyes per piece. Dust the freshly cut pieces with micronized sulfur and allow to dry a day or two before planting to minimize the chance of rot. Plant them outside about the same time you would plant other hardy annuals—when the danger of frost is mostly gone (mid-May). To get a jump on the season, cannas can be started indoors 4 to 6 weeks ahead of the last frost date.How 

I have read articles that indicate specific soil temperatures are required before planting certain plants in the spring. How do I determine what the soil temperature is? Are there actual soil thermometers to use?

The uptake of water and nutrients is greatly affected by soil temperature. Seed germination is also affected by temperature. Planting before the soil is sufficiently warm can delay or prevent the establishment of many plants.

As you might imagine, not all plants are the same. Cool season crops like peas, cabbage, lettuce and onions can be planted and will establish when soil temperatures are still quite cool (45 degrees Fahrenheit). Tomatoes and peppers, however, will not grow well until soil temperatures reach 59 degrees or more. Melons and cucumbers need temperatures in the middle 60’s to take off. Most flower and herb seeds require a minimum temperature of 62 degrees, but will germinate faster if warmer.

Soil thermometers are available at many garden centers. Expect to pay between $10 and $20 for a good thermometer or a good deal more if you want something fancy. Insert the thermometer 4 to 6 inches in the ground for your reading. Remember that not all areas of your yard will warm up at the same time. Soil type, sun exposure and adjacent structures all influence the rate of warming. Your soil thermometer can take the guesswork out of the equation and allow you to get the earliest possible start.

I frequently read tips that recommend the ideal time to prune a plant is when it is “dormant.” How do I know when a plant has gone dormant?

Dormancy usually refers to the time that the leaves drop off and lasts until the plant leafs out in the spring. For many plants, the best time to do any major pruning would be in early spring before it starts leafing out.

Trees such as birch and maple are usually better pruned in late spring when the plant has fully leafed out. Otherwise they have a tendency to “bleed” sap at the points where they were cut. Evergreen trees are best pruned in late spring just before the “candles” of new growth harden off. As you can see, it is more important to know what kind of plant that you need to prune, and not to just prune anything just because it is dormant, because many plants will break that “rule.”