#TeachingTuesday: Red-Twig Dogwood

Usually, when people think of “dogwoods”, they think of the eastern flowering dogwood (Cornus florida), a small, native, understory tree with showy white or pink blooms in the spring. But did you know there are lots of different kinds of dogwoods, including both trees and shrubs? This morning, our crews were trained in identification and maintenance of red-twig dogwoods (Cornus sericea), which are beautiful shrubs with brilliant red stems that look absolutely stunning in the winter–especially in the snow! The stems can also be cut and used in holiday floral arrangements.

A winter landscape at JC Raulston Arboretum: Red-twig dogwoods in the foreground with maidengrasses and pine trees in the background.

Red-twig dogwoods, also known as red-osier dogwoods, are native to most of Canada and the western and northern regions of the United States. They are shrubs that truly have 4 seasons of interest. In the spring, they leaf out with fresh green foliage; in early summer, they bloom with clusters of tiny white flowers that mature into red berries; in fall, the leaves develop a deep, purplish-red color; and in winter, the leaves drop to reveal the brilliant red stems. They can grow up to 9 feet tall and wide if left natural, but typically a rejuvenation pruning schedule is followed to retain the bright red young stems (more on this below). They tolerate sun to part-shade and wet to dry soils, support many species of local insects and wildlife.

Maintenance

Red-twig dogwoods are pretty low-maintenance shrubs. In natural areas where size is not an issue, they can be left to their own devices. However, as the stems mature, they will lose the intensity of the red color, and will eventually turn gray after a few years. So, periodically, the old stems need to be pruned out. Ideally this would be done once per year in the winter, and the oldest stems that are starting to lose their color would be pruned all the way to the ground. Be careful not to prune new shrubs that have been planted within the last year, and don’t remove more than 1/3 of the total stalks in one year.

ID Tips

  • The bright red stems are pretty good indicator that a shrub is a red-twig dogwood (or closely related species).
  • The stems will have light tan “lenticels”, which are small, corky bumps or lines on plant stems or trunks that allow gases to interchange between the air and the interior plant cells.
  • The leaf shape and venation (vein pattern) are similar to eastern flowering dogwood, although the leaf may feel thicker and tougher.
  • The flower clusters are white, and each floret (tiny flower) has 4 petals and a reddish center.
  • In late summer, the flower clusters will develop into clusters of red berries, which will persist through the fall.
Notice the pattern of light tan dots (called “lenticels”) covering the stems.
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#TeachingTuesday: Creeping Jenny

This week, we’re focusing on a vigorous little groundcover called creeping Jenny (Lysimachia nummularia). In our area, creeping Jenny is a part-shade perennial, which grows best in moist garden soils or containers. It should not be allowed to grow in areas where it could spread to natural habitats, as it can be a bit aggressive. It is ideal for planting around large stepping stones, as it can take some light foot traffic.

Winter foliage of creeping Jenny, with lots of new shoots!

For best success, you should avoid planting creeping Jenny in areas with direct afternoon sunlight, as this can cause wilting and blanching of leaves. While it requires constant moisture, the soil should be well-drained and not boggy. Wet soils will lead to root rot. Heavily damaged foliage may be cut back if needed in late winter or early spring before new shoots appear.

ID Tips

  • Creeping Jenny is very easy to identify. The leaves are small, round, and arranged in flat, opposite pairs along creeping stems that stay low to the ground and will trail over walls or containers.
  • The flowers are small, yellow, and bell-shaped. The flowers often fade into the background of the bright trailing foliage, which is most often a chartreuse color in gardens (though it also comes in a medium green color). The foliage may turn bronze in winter.
Note the characteristic pairs of round leaves along the stems.

#TeachingTuesday: Liriope vs. Mondo Grass

Last week we had to cancel our usual training session due to extremely cold morning temperatures! We delayed our crews coming in for an hour and a half until the sun could come up and raise the temps. Fortunately, we’re not experiencing the current polar vortex dip like the Midwest is! We are hoping that everyone in the Chicago area stays safe and warm.

Today we covered an important topic with our maintenance crews: how to tell the difference between liriope and mondo grass, and which one should be cut back over the next month or so. There are two main types of liriope – clumping (Liriope muscari) and spreading (Liriope spicata). The neat clumps and broader foliage of L. muscari make it easy to tell apart, but L. spicata and mondo grass (Ophiopogon japonicus) look very similar. Both are very common groundcovers in NC, and ours crews will be spending a lot of time working with these plants on our clients’ properties as we start gearing up for spring.

Key Differences – ID Tips

  • The leaves of mondo grass are more narrow than those of liriope.
  • The berries of mondo grass are bright blue, while liriope berries are black.
  • The flower stalks of liriope are usually quite showy, and stick out above the foliage. You will not usually see the flower stalks of mondo grass, as they are typically shorter and hidden beneath the foliage. Even in the winter once the flowers and berries are all gone, you will notice more old stalks on the liriope, and will not usually see any in the mondo grass.
  • Mondo grass plants are typically shorter than liriope, and may be darker green.
  • Mondo grass leaves are less likely to have winter discoloration or signs of insect or disease damage than liriope.

Winter Cutback

Because Mondo grass is less susceptible to winter discoloration and damage due to insects and diseases, it does not usually need to be cut back in the late winter/early spring. Liriope, however, grows very quickly and does best when cut back once every year. This also gives you a chance to remove fungal spores and scale insects that may be overwintering on the old foliage. Make sure to cut the foliage back BEFORE the new foliage begins to emerge–February is usually a good time of year for NC.

Liriope can be cut back in a few different ways, depending on how large of an area you are cutting back. For small areas, hands shears or electric shears may the easiest route, but for very large areas, a push mower may be used. Make sure to use a clean, sharp blade set no lower than 3″. Remove all of the cut foliage to prevent spread of insect pests or diseases. If the beds need to be mulched, make sure to not bury the plant crowns, as this will lead to crown rot.

Liriope – Liriope spicata
Mondo grass – Ophiopogon japonicus

#TeachingTuesday: Wintercreeper

Hello and Happy New Year! We’re trying to get back into our normal routine after the chaos of the holidays, crazy weather, and switching over our operations software system. Here’s our first plant ID post of the year!

Euonymus fortunei, Wintercreeper

Chances are you have seen this plant before many a time! Gardeners may understand the tenuous relationship we have with this plant, as it can be extremely aggressive to the point of invasiveness in some scenarios, but can also be a versatile groundcover with nice winter color. It is a woody vine that forms a sprawling mat on the ground, but can grow into a shrub in some cases. Like English ivy, it will climb when it reaches a vertical surface, such as a wall, tree, or telephone pole, so it requires diligent pruning. It can grow in sun or shade, and will tolerate most conditions except wet soils. There are many cultivars available, offering variations in color.

Maintenance Tips

  • Be sure to prune it regularly to prevent spreading into unwanted areas or up tree trunks
  • If it grows up a surface, it will start producing seeds, causing it to spread even more rapidly. Avoid using this plant on walls or fences.
  • Maintain good soil drainage to avoid pests and diseases such as anthracnose, crown gall, powdery mildew, aphids, and scale.

ID Tips

  • The woody stems and opposite leaves are similar to many other vines such as Asiatic jasmine (Trachelospermum asiaticum) and vinca (Vinca spp.)
  • Unlike vinca and Asiatic jasmine, wintercreeper leaves will have slightly toothed edges (see images below)
  • Wintercreeper will grow more vigorously and try to climb more than Asiatic jasmine or vinca.
  • Asiatic jasmine will have white flowers, vinca will have periwinkle flowers, and wintercreeper will not normally flower at all. If it starts climbing, it may start producing clusters of tiny, pale green, unattractive flowers.

#TeachingTuesday: Muhly Grass

Because of the short weeks we had due to rain and the Thanksgiving holiday, today we had our first new plant for plant identification training in 3 weeks! Last week, the crews reviewed the plants they learned in November: Carex ‘Evergold’, Chinese pistache, and tea olive.

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The Myatt Landscaping office is ready for the holidays!

Pink muhly grass, or Muhlenbergia capillaris, is one of my top favorite plants. Best grouped in masses, this ornamental native grass blooms in fall creating the effect of fluffy, pink clouds. These grasses can add ethereal beauty to the home garden perennial border, or a stunning display of fall color in public parks and along highways in mass plantings. In late fall, the pink flowers develop into gray-purple seeds, which are eaten by birds and small mammals. The seedheads then fade to a light buff color, and retain their attractiveness until spring, adding texture and movement to the winter landscape. They thrive in full sun, and are tolerant of heat, humidity, drought, poor soil, and are also highly tolerant of salt and deer! These grasses do well in every part of NC as long as they are not planted in shady or wet areas.

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Muhlenbergia capillaris (Photo credit: Mark Turner)

Although the most widely accepted common name is pink muhly grass, more recently it is being referred to as simply “muhly grass,” because of a white-flowered variant developed in the early 2000’s, Muhlenbergia capillaris ‘White Cloud.’ White Cloud muhly grass is a bit more upright than the species.

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Muhlenbergia ‘White Cloud’ in the plant holding area at our office.

Maintenance Tips

Both pink and white muhly grass are very low maintenance. They typically do not need to be cut back the first year after they are planted, but may need to be cut back or thinned in early spring after they are well established. This will help ensure that they have enough air circulation, which will protect against disease.

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Muhly grass in winter (Photo credit: JC Raulston Arboretum)

ID Tips

  • The leaves are dark green, thin, and wiry, and grow in a neat, rounded clump. There aren’t many other grasses that look similar. There are many species of Muhlenbergia, but M. capillaris is the most commonly available one.
  • The blooms are unmistakable–panicles (clusters) of pink to deep rose hair-like filaments.

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#TeachingTuesday: Tea Olive

Today for #TeachingTuesday, we will cover two species of tea olive: Osmanthus fragrans and Osmanthus x fortunei. Tea olive is also known as false holly, or simply ‘osmanthus.’ Personally, tea olive is one of my all-time favorite shrubs. I have fond memories of walking across the NC State campus in late October and smelling that sweet, sweet fragrance, then looking around trying to find the large shrub it was coming from (sometimes more than 50 feet away!). Plant these evergreen shrubs near windows, porches, and outdoor living areas to enjoy the enchanting scent through the fall. The shrubs/small trees are long-lived and virtually free of pests and diseases.

Osmanthus fragrans – Fragrant Tea Olive

The fragrant tea olive is, unsurprisingly, the most fragrant Osmanthus species. However, it is also the least cold hardy, and is only marginally successful in zone 8 (it prefers zones 9-11). For reference, Raleigh-Durham is zone 7b/8a, Wilmington is zone 8a, and Charleston, SC is zone 8b/9a. We see it more on coastal properties, but it can also be grown as a container plant, or in sheltered locations with winter protection.

There is also an orange-flowered form, Osmanthus fragrans f. aurantiacus, which is slightly more cold-tolerant than the species.

 

Osmanthus x fortunei – Fortune’s Tea Olive

Fortune’s osmanthus, or Fortune’s tea olive, is the most common species used in our area. It is a hybrid between Osmanthus fragrans and Osmanthus heterophyllus (false holly). Like its parent, it has small, white, highly fragrant flowers, and blooms in October-November, but is much more cold-hardy, surviving throughout zone 7. It has been around in the western horticultural trade since 1856, when it was introduced to Britain from Japan.

Fortune’s tea olive can be grown as a shrub, a small- to medium-sized tree, or even a hedge. Its spiny leaves make it very resistant to deer damage, and it is also drought tolerant, and somewhat tolerant to shade and salt.

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A large screen of Osmanthus x fortunei

ID Tips

  • Although at first glance many tea olive species may look similar to hollies, there is an easy trick to tell the difference: tea olive leaves are always in opposite pairs, while holly leaves alternate along the stem.
  • Fragrant tea olive leaves are slightly larger and longer than Fortune’s tea olive leaves, and will have either entire margins (meaning smooth edges) or dentate margins (meaning finely toothed edges). The tip of the leaf is not spiny.
  • Fortune’s tea olive leaves are smaller and more oval-shaped, and will have a spiny tip at the point of each leaf. There are three kinds of leaves on Fortune’s tea olive: the juvenile leaves (leaves near the base of the plant), which will have 10-12 triangular, spiny teeth on each side (the younger, the spinier). The mature leaves, which are found on the upper branches of the shrub/tree, will have smooth edges, but will still have the spiny point at the tip. In the middle, there will be leaves that have a few spines near the tip of the leaf, but smooth edges near the base.

Do you have more tips for identifying tea olives? Leave a comment!

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All Osmanthus species have leaves in opposite pairs.

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Note the spines disappearing toward the base.

 

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Individual flowers are very small, but very fragrant!

#TeachingTuesday: Chinese Pistache

This week, the Chinese pistache trees at our office burst into flaming glory, showcasing their brilliant fall color palettes of yellows, oranges, red, and even pinks and deep maroons. We couldn’t ignore it, so it’s our plant of the week!

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Chinese pistache, or, scientifically, Pistacia chinensis, is a tough, medium-sized tree that fares equally well as a landscape specimen or urban street tree. It is drought tolerant and has no serious pests or diseases. Renowned plantsman Michael Dirr describes the tree as gawky when young in his Manual of Woody Landscape Plants, but it matures into a beautiful specimen tree, rivaling the sugar maple as one of the prettiest trees for fall color in the south.

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Fun Facts

  • Pistacia chinensis is a cousin to the pistachio tree (Pistacia vera), which produces the pistachio nut.
  • Chinese pistache trees have separate male and female flowers, and the flowers are on separate trees. This type of flowering is called dioecious, and some other common examples of dioecious trees include hollies and ginkgos.
  • The stems of Chinese pistache have a strong odor when bruised or crushed.

ID Tips

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Notice the 5 pairs of opposite leaflets and no terminal leaflet.

  • The leaves of Chinese pistache are compound, which means a single leaf is made up of multiple small “leaflets.” The leaflets are arranged opposite of one another, and are almost always in 5 or 6 pairs. Unlike many nut trees, such as walnut, pecan, and hickory, there is no terminal leaflet.
  • The buds are large, oval-shaped, and dark brown or blackish in color. There are multiple clustered buds at the branch tips (terminal buds).
  • The buds are arranged alternately along the stem.

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Terminal bud cluster

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Notice the alternating buds along the stem (the buds are not in pairs).

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Fruit only develops on female trees, and can range in color from blue to red. The fruit is eaten by birds.