I recently returned from "The Gardens of England" tour coordinated for Illinois Master Gardeners, which included the Royal Horticulture Society (RHS) Hampton Court Palace Flower Show, the largest flower show in the world. Imagine a flower show that encompasses 25 acres and offers an opportunity for guests to see every possible herbaceous perennial (not really, it just seemed like it) throughout stunning design gardens and floral displays—and everything was labelled, so no guessing the identity of unknown plants! And behind many of the individual company design gardens or floral displays were the individual plants for sale! Needless to say, my husband was grateful that I was not in a position to buy plants because it would have been an epic plant purchase if I had been in the States and had a large moving van.

In addition to the significant plant component of the show, just about anything related to garden lifestyle was available for sale as well, from outdoor seating and greenhouses to outdoor garden-wear and tools. I believe I experienced for the first time in my life plant and garden paraphernalia overload…it didn't take me long to recover though. One of the first things I did upon returning home was to order bulbs, specifically Allium 'Forelock' (see top picture). The John Scheepers' catalog describes the flower as "3 inches around with an unruly tuft of white-tipped, mahogany-red flowers exploding out of the top of its head." It was that tuft of florets that really endeared the plant to me…can't wait to grow some for myself.

Late summer through early fall is the best time to divide and plant bearded iris. The reason being that iris need four to six weeks following flowering for new rhizomes to fully develop before digging and dividing. That's why most iris plant sales are held later in the growing year and why nurseries don't ship bare root plants until mid- to late-summer.

Cultivars vary in growth rate, but on average, expect three or more fan increases each year from each "mother' rhizome." Some cultivars are slow to increase with less than three fan increases, whereas others rapidly multiply the mother rhizome by a factor of eight or more. I find in general, the more beautiful the bloom, the slower it is to increase. Most gardeners find it necessary to dig, divide and replant new divisions every three to four years. A gardener should definitely have a plan in place for where new iris rhizome divisions will go before digging, whether that be a new patch of ground or maybe a gift to a friend.

From experience, dig one clump at a time to avoid mixing up cultivars. Once the clump is dug, cut away individual new rhizomes from the mother rhizome with pruning shears or a knife. With a permanent marker, you can write the cultivar name directly on a leaf blade. Discard the old mother rhizome. Each new division will look like the original rhizome you planted after cutting the leaves back in an arrow or inverted vee shape, with the point centered about four to five inches above the rhizome.

At this point, the rhizome divisions are now ready to plant. Iris grow best where they will receive six to eight hours of direct sunlight. Soil should retain uniform moisture but still be well drained. Probably the most common mistake gardeners make with planting iris is planting the rhizome too deep. Despite its bulb-like appearance, a rhizome is actually modified stem tissue that grows best at or just below the soil surface.

Plant spacing can vary. It really depends on how often you want to dig and divide. The closer you plant, the sooner plants grow together and need to be divided. Plants spaced 12 to 18 inches apart allow a gardener to put off division for three to five years. Planting less than 12 inches apart will accelerate the process to every two to three years.