When I fertilize certain annuals, why is there more foliage growth than flowers? I believe cosmos are one of them.

It could be what you are fertilizing with. Complete fertilizers contain three primary nutrients, listed as three numbers on the fertilizer package, such as 12-12-6. They represent the percent of nitrogen, phosphorus and potash contained in that product. These three numbers appear on all fertilizing products and are always listed in the aforementioned order. A properly balanced fertilizer, in combination with other critical growing factors such as water and sunlight, can promote growth and flowering as well as enhance vigor, general hardiness and disease resistanc

If one of these critical elements is lacking or is extremely out of balance with the other nutrients, the fertilized plant may not perform as expected. For example, if you used a lawn fertilizer with an analysis of 34-4-4 on your cosmos, the overbalance of nitrogen is likely to produce a very bushy, green plant with few flowers. A better combination of nutrients would be an evenly balanced fertilizer such as a 12-12-12 or a 20-20-20. Once the plant is well established, a fertilizer higher in phosphorus (the middle number) will generally enhance and improve the plant’s ability to produce abundant flowers. Consider using a 5-10-5 granular fertilizer or giving the plants a “punch” of water soluble fertilizer (fertilizers intended to be mixed with water and used as a watering solution) such as 10-54-10.

Can tulips be divided? If so, when and how do I do it?

The sad truth is, tulips are not a truly dependable perennial in Michigan. Our springs are often too brief, starting late and becoming summer almost overnight. If summer comes on quickly, the foliage may die down before it has time to replenish the spent food reserves. The result is a smaller bulb (than the one you originally planted) that survives to the following spring. Tulip beds in Michigan produce their best show in the spring following fall planting. Each successive year produces fewer and smaller flowers. Tulip division becomes a moot point.

Another alternative is to plant early-blooming tulips so the foliage can remain longer, thus re-energizing the bulb sufficiently. Or, you can simply treat tulips as an annual, replacing the beds with top-size bulbs the following fall. Keep in mind that other spring-flowering bulbs are more dependable perennials for our area. Daffodils (Narcissus) will return year after year, and multiply in the process.

When is it safe to put terracotta pots back outside?

It is safe to put clay pots back outside when temperatures consistently stay above freezing.