Plants of Merit

This week, a look at some of my favorite plants that for one reason or another I consider plants of merit.

Here you’ll find some suggestions for perennials, shrubs and a few trees. Each plant mentioned has been in the garden for at least two years and a few for over 15 years. Some may be hard to find so if you’re having trouble locating any try places like Marders and Fowler’s.

I tried growing Kniphofia back in the early 1970s. These “Red Hot Pokers,” then called Tritoma and also known as Torch Lilies, were only available as the Pfitzer hybrids, and no matter how many times I tried, they never overwintered. But more recently, hybridizers have come up with lime green versions, pink ones and near-white ones. As a traditionalist in the garden I’m much more interested in the red types. After all, they are called “Red Hot Pokers.”

Many are now winter hardy with some reputed to be hardy to zone 5. The foliage is swordlike and under an inch wide with each leaf emanating from a central crown. I’ve been growing the variety “Joker’s Wild” for several years now and really like this plant. With five plants in a 10-square-foot area they send up spikes, or pokers, in mid to late June. The flowers are red/orange with hints of yellow and each flower spike can be 24 to 36 inches tall. The flowers last about two weeks, and I just noticed that as the flowers begin to fade several of the plants are sending up new shoots so the blooming period can be three to four weeks.

The plants will not do well in wet soil, and if they’re constantly irrigated you and they will be disappointed. The stems should be cut when the flowers fade and show no color and if necessary the foliage can then be trimmed to six inches. No winter protection is needed but they do require a loose, fast draining soil.

Having grown 25 varieties of Echinacea there are only two of the hybrids left in my garden. The other 23 (E. purpurea thrives in several spots but isn’t a hybrid) are long gone. These are Hot Papaya and Supreme Cantaloupe. Hot Papaya is a really striking red but it’s in a spot where the lilacs have been crowding it a bit. No matter, this plant has stems of 24 to 36 inches that simply reached up through some rose foliage and are blooming with glorious abandon.

Supreme Cantaloupe has a much more subtle coloration with the color being true to name. In full sun it begins to bloom in late June and can continue blooming for eight to 12 weeks. As a non-seed-producing hybrid the spent flowers don’t need to be cut but it does make the plant look much nicer. Supreme Cantaloupe does seem a bit susceptible to mildew so it shouldn’t be watered overhead or by irrigation. Both of these (as well as the species) make great cut flowers.

I have a few maples on the property, and while each has its attributes, my notes for Acer shirasawanum, or the fullmoon maple, says it all: “Simply stunning.”

While considered a yellow-leaved maple the foliage has several color changes during the season with the leaves exposed to the sun being yellow while those shaded below are green. The leaves are also often edged in red. Late in the summer the foliage morphs into shades of red/orange that gets more intense as fall approaches.

This isn’t a large tree as it only grows to about 20 feet tall max and about 15 feet wide. Not fast growing, it takes about 10 to 15 years to mature. I’ve had no disease or insect problems with it, and it can be grown as an understory plant but the colors are most spectacular when grown in full sun.

My other favorite maple, aside from my thread-leaved varieties, is called Acer griseum x nikoense “Shaved Chocolate.” It belongs in the paperbark group of maples where the bark exfoliates (sheds from the surface). Imagine a tree trunk about an inch and a half in diameter made out of a dark chocolate that’s been shaved with a plane. You can read more about the paperbark maples here: tinyurl.com/mv2c8a2u.

My tree came from Roy Klehm, who hybridized this variety, and while I’ve had it since 2013 it’s only 10 feet tall and 5 feet wide and will only grow to about 16 feet tall. Yes, a slow grower. The foliage is not like any maple leaf you may be familiar with in terms of shape. In addition to its bark that comes off in curled flakes, the fall foliage color is a vibrant red.

Back to the perennials, I have an interesting collection of Ligularias. Most gardeners are familiar with the variety “The Rocket,” which grows to 3 to 5 feet and has bright yellow flower spikes resembling the flames shooting from a — you guessed it — rocket. The flowers are small but cover a long stalk. A smaller Ligularia called “Bottle Rocket” is very similar but only grows half as tall and wide. The foliage is green on both and the edges of the leaves are sharply serrated giving the foliage an unusual character.

But this genus has some great surprises in it with incredible foliage patterns, colors and flower variations. All prefer a moist soil and some are prone to slug damage and they will grow in part to full high shade. Manage the slugs early in the season and the plants will be fine. I’ve had no disease or insect problems and the flowers do seem to attract several species of butterflies.

The variety L. japonica “Frosted Flecks” has leaves more akin in size to a giant split-leaf Philodendron all emerging from a subsurface crown. The leaves are also green but with flecks making it appear that milk was spilled on them. The flower, however, is daisy-like on stems almost 3 feet tall.

Ligularia denticulata “Othello” has dark-colored bronze foliage that’s almost reddish purple. The daisy-like flowers are set on stalks less than 3 feet tall and a yellow-orange color. New leaves emerge a purplish-red but mature to brownish green on top and more purple underneath. Othello is very similar to the variety Desdemona except that Othello is slightly smaller with slightly smaller flowers.

The variety L. “Osiris Café Noir” has deep purple-black foliage that matures to a bronze. The flowers age daisy-like in clusters at the end of 3-foot stems. Weston Nurseries in Massachusetts refers to it as having “attractive large serrated heart-shaped leaves emerging deep purple in spring, turning olive green in color with showy gold variegation and tinges of coppery-bronze throughout the season.”

L. denticulata “Britt Marie Crawford” is one of the latest blooming Ligularias as it blooms from mid-August. Among the Ligularias this one has more rounded foliage but the edges of the leaves are serrated as if a pinking shears has been taken to them. The golden yellow flowers are on shorter stalks and in clusters so this Ligularia should be planted in front of taller ones or closer to the edge of the gardens.

Ligularia “Chinese Dragon” has been in the garden since 2012 and is an introduction from Plant Delights nursery. It was discovered in Sichuan, China, in 2005 with seeds brought back to the United States. The leaves are cutleaf, giving them interesting character among the other Ligularias and the daisy-like flowers are atop 4-foot stems making them stand above all the others in this group. This may be one of the earliest Ligularias to emerge in the spring so if there’s a threat of a late frost just throw some leaves or hay over it (lightly) and remove in the morning.

While the Ligularias can add a great deal of interest, contrast and color to the garden, keep in mind that they must be in moist soil. At the slightest hint of drying out some varieties will wilt and will need to be quickly revived. Also remember to keep the slugs under control to keep the foliage in great shape.

Lastly for this week’s review are some hydrangeas. My records tell me that in the past 15 years I’ve tried 15 varieties. Maybe five are standouts or otherwise interesting. Hydrangea aborescens “Invincible Mini Mauvette” has medium-sized mophead flowers that bloom in a deep mauve-violet color. The blooms appear fairly early in the summer and last well into the fall. What gives this variety special appeal is that it’s got a semi-dwarf habit at 3 feet tall and wide. A nice hydrangea for the smaller yard or property.

H. paniculata “Little Quick Fire” is one of my earliest hydrangeas to flower, and when the flowers emerge they are pure white. As the season progresses there is a subtle change in late July as pink starts to emerge in the flowers, and by early August the entire shrub becomes pink to pink/red. The flowers then remain in this state for the rest of the season. The shrub is only about 4 feet tall and wide making it useful in many situations. Mine are under a maple tree at a border edge and only get three hours of direct sun and they don’t seem to mind it at all.

This hydrangea is pruned in late winter or early spring, and since it only blooms on new wood it needs annual pruning. Branches should never be pruned more than a third of their length. One application of an organic fertilizer in the spring will help and it prefers to be in a drier soil as opposed to wet. Never plant in a spot where it receives full sun all day.

I’m also a big fan of H. aborescens “Invincible Spirit 2.” It’s a full sized Annabelle type that reblooms and stays in flower into the fall. About 4 feet tall and as wide, it’s been a great performer with no hardiness issues at all. Prune in early spring, reducing the entire plant by about one third.

So many more to tell you about so maybe more suggestions in a few weeks. Keep growing.