Getting Your Perennials to Grow – and Bloom!
Neil Zikmund, Anoka County Master Gardener
Frustrated that your plants are not growing, or blooming, or are looking sad? What’s going on? You water regularly, you planted per the directions on the tag but still pine for the day your plants reach their full potential. One, two, three is my code for soil, sun, water. Those are the keys, and they are simple; if everything else is perfect, which seldom happens. There is a fourth, but I saved it until the end.
Soil is the most difficult factor, in that short soil testing, it’s difficult to know. If you are unsure or if cost is a deterrent, you can still succeed without testing. The plant tag should give you enough information. For those planting in the Anoka County Sand Plain, any tag stating well-drained soil will work – IF the soil fertility (PH) is good. That’s where the soil test would help. However, adding compost to the soil when you plant is beneficial. Leaf compost is a wonderful natural fertilizer and works great. Mix the sandy soil with the compost when planting. Conifers, rhododendron, and azaleas prefer acidic soil, so adding peat moss will increase the acidity of the soil.
Sun is probably the least flexible component for success. Unless you have full sun or full shade, it depends on your yard! Most yards may have partial sun/shade, but if the tag indicates full sun, at least six hours of direct/intense sun is needed. Anything short of that usually results in poorer performance. Partial shade or partial sun depends on the quantity of time exposed, the type of sun: if it's dappled sun, or early morning sun, or afternoon sun. Plant the same species in two or three different locations with similar shade/sun conditions, and you might be amazed at the difference.
Radiated/deflected sun is a force multiplier. Planting next to a structure, or anything stone/masonry that will impact the performance of the plant. Joe Pye weed and Martagon lilies are just two examples of plants that like deflected sun.
Water is probably the easiest of the three to control. Just like soil and sun, the tag tells you how much water and if it says wet soils, then the soil must be kept wet. If you're unable to maintain that moisture, save yourself the disappointment, and do not plant it where you wanted it; the plant will not thrive.
There is a fourth element – fertilizer – that can be used once the plant is established. Fertilizing is also a force multiplier. I use a light application of 10-10-10 around mid-April. I often work in compost in the top inch of soil as well. I fertilize again in early August, especially for those perennials that bloom in August and September.
Below left – Brunerra with its preferred dappled sun
Below right – Brunerra with two to three hours of direct late afternoon sun
These plants are within 25’ of each other with the same soil and same water. The sun's impact is the difference.
