#TeachingTuesday: Carex rosea, Rosy Sedge

Going into fall, we always like to review different Carex species with our crews. One reason is that we use carex in our fall container plantings, and another is that we want to prevent any accidental cutbacks. The genus “Carex” is made up of grass-like plants called sedges, and although they look like grasses, they grow in different conditions and require different maintenance. Carex looks great in a container because it adds a full, yet delicate texture that moves like a waterfall in the wind. It comes in many different shades of yellow and green, with variegated types as well. On some, the inflorescences (seedheads) are hardly noticeable, and on others they are somewhat attractive. Today, we will specifically look at Carex rosea, the rosy sedge.

Rosy sedge is native to North America, and grows naturally in bottomlands and deciduous forests. It is often found in damp areas such as along streams and ponds, or rocky crevices. It grows in clumps, but will spread slowly by rhizomes (thick roots, like in daylilies) in a favorable environment. This plant is great for shade gardeners, because it will tolerate both wet and dry soils, and it can be used in rain gardens. It can also be grown as a lawn alternative or ground cover (but don’t mow it like grass!). The foliage is a nice medium to dark green, slightly shiny, and fine-textured. The “rosy” part of the name comes from the rosy tint on part of the seedheads.

Maintenance

Maintenance for rosy sedge is next to non-existent! It doesn’t generally need any trimming, unless significant browning occurs in winter. Avoid planting in very windy locations and make sure the plants receive enough water during winter to avoid excessive browning.

ID Tips

  • The leaves of rosy sedge are creased along the center, causing a ‘V’ shape when cut in cross-section.
  • Rosy sedge has very narrow solid green leaves, quite similar to Carex pennsylvanica. Sedge leaves taper gradually to a very long, thin, wiry point which sometimes curls.
  • Most sedges have small, brown, tufty seedheads, and what sets rosy sedges apart is the white fluffy tufts on a rosy brown base.
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#TeachingTuesday: Japanese Maple

We took a short break from the blog this summer, but are happy to be back this week with one of our favorite trees–the Japanese maple, Acer palmatum. This species has an incredible variety of sizes, colors, leaf shapes, and habits. Ranging in height from tiny dwarfs up to medium-size trees, similar to a redbud or dogwood, Japanese maples also come in weeping or upright habit. While leaf color and texture in the summer and fall are some of the most recognizable attributes, the architecture of the truck and branches are stunning year-round (but most noticeable in winter and spring), making this a truly 4-season addition to the landscape.

Note the beautiful twisting structure of the branches.
Photo credit: Jeanne Wilkinson
JCRA Photograph Collection

Pruning

Japanese maples require very little pruning. They should never be sheared or topped, as this will ruin the structure of the tree. The only pruning required is occasional selective pruning to remove branches that are diseased, crossing or rubbing on other branches (this can create a wound where pathogens can enter), or need to be removed to increase air or light infiltration (thinning). When in doubt, err on the side of caution or ask a professional. Remember that you can always prune a branch later, but you can’t put it back once you’ve cut it!

ID Tips

  • The leaves of Japanese maples have incredible variety, as you can see above, but they will always grow in opposite pairs along the stems, and will always have 5-11 palmate lobes (lobes that radiate from a central point, like fingers from a palm). Sometimes, the leaves will appear finely dissected, or lacy, especially on weeping varieties. Compared to other species of maple, the leaves are smaller, and the lobes are more delicate, pronounced, and pointed. See images above.
  • The seeds of maple trees are a type of seed called “samaras” and you probably called them helicopters and played with them as a child. Japanese maples typically have pink to red samaras, and they are smaller than other species of maple. See below.
  • The trunk of a Japanese maple is typically more twisted and has smoother bark than other types of maples. The immature bark is often pale green, but may also be colored coral, pinkish, red, or purple depending on the cultivar.
Acer p. ‘Shishi Yatsubasa’
Photo credit: Maryann Debski
JCRA Photography Collection

Going into fall, be on the lookout for outstanding color from these magnificent trees!

Visit the JC Raulston Arboretum to see an extensive collection of different Japanese maples, like this large weeping specimen (Acer p. ‘Green Hornet’).
Photo credit: Susan Bailey
JCRA Photography Collection

#TeachingTuesday: Rudbeckia, AKA Black-eyed Susans

Rudbeckia fulgida var. sullivantii ‘Goldsturm’ looks enchanting in a perennial border.

Today our crews reviewed one of the most popular perennials, black-eyed susans, or Rudbeckia sp. The main species are:

  • Rudbeckia fulgida, black-eyed susan (‘Goldsturm’ is the most common cultivar)
  • Rudbeckia triloba, black-eyed susan
  • Rudbeckia laciniata, cutleaf coneflower
  • Rudbeckia maxima, giant coneflower
  • Rudbeckia hirta, black-eyed susan (This species is short-lived and often used as an annual because it does not come back reliably after winter.)
Rudbeckia laciniata looks beautiful rambling in natural areas.

Tips for Growing Rudbeckia

All rudbeckias are native to North America, and some are native to the southeast, such as the giant coneflower. They are excellent for use in perennial borders, pollinator gardens, natural areas, and mass plantings. They do spread, so they tend to do best planted in large swaths and allowed to colonize. They bloom longer if deadheaded, but leaving the seedheads intact will attract the birds that feed on them. The spent seedheads can actually look quite attractive in the winter landscape if left in natural areas, though sometimes they are beaten down by the rain and can appear messy. The flowers can also be used as cut flowers in arrangements.

Rudbeckias grow best in full sun, with well-drained soil, thought once established they can be quite tolerant of drought or poor soils. In wet soils, they are prone to root rot. They do not require much care to look great, and are an excellent choice for beginner gardeners experimenting with perennials. As with most perennials, fall is the best time for planting, but mid-spring is the next best time. Planting in fall allows time for the root system to grow and establish before the heat and drought stress of summer. Most pest and disease problems can be avoided with proper plant spacing and adequate soil drainage.

Rudbeckia maxima is very large, and has distinct bluish gray waxy leaves. Stunning at the back of a border.

ID Tips

  • Typically with most Rudbeckia species, the leaves and stems grow from a basal rosette (single clump in the center of the plant), and the leaves are dark green and lance-shaped, usually with lobed edges. They may feel rough like sandpaper to the touch. The leaf shape can vary quite a bit in appearance from species to species.
  • The flowers are quite similar in shape to Echinacea. They have a central disk which may be rounded or cone-shaped, usually dark brown in color, but may also be yellow or greenish in some species. The petals (ray florets, if you want to be technical) radiate out from the central cone and are usually reflexed, drooping downward away from the cone. The petals are yellow, ranging from bright clear yellow to deep golden. On R. hirta, the flowers may be reddish brown around the cone, fading to yellow near the petals tips. Some varieties have been bred that are completely red (ruddy, brownish red).
  • In winter climates with freezing temperatures, the plants may die back completely to the ground, or there may be a small basal rosette of leaves remaining.
Rudbeckia hirta growing wild in a field.
A red Rudbeckia hirta cultivar.

#TeachingTuesday: Angelonia, Wax Begonias, and Lantana

The first summer flowers were installed about 6 weeks ago, so our crews are starting to pinch back some of the more vigorous growers to keep them in check. For Teaching Tuesday, we reviewed these three superstar performers for hot summers. All three perform well in both flower beds and containers.

Angelonia (Angelonia angustifolia)

A tall, vigorous annual, angelonia looks great in the back row of a flower border, or the center of a container. It is heat and drought tolerant, and does not need pruning except trimming back from walkways or other fixtures as needed. The blooms range in color from blue and purple to pink and even white, and they keep blooming all season.

A mix of blue and white Angelonia in an annual bed at the entrance to a business park.
© 2019 Myatt Landscaping Concepts, Inc.

Wax Begonia (Begonia semperflorens)

Compact annual plant with fleshy leaves and stems. Leaves come in green or bronze color, and the flower colors range from white to pink to deep red. Wax begonias are mildly drought tolerant and are deer resistant.

A border of Wax Begonias around mixed Coleus, Caladiums, and Hibiscus.
Photo credit: Jenna Meeks

Lantana (Lantana camara)

Lantana is technically a tropical shrub, and will grow back in warmer climates, such as the NC coastal plain, SC and GA. The cultivar ‘Miss Huff’ is cold hardy even in the piedmont of NC! It is very salt tolerant, deer resistant, and will attract butterflies and other pollinators. Colors range from white/yellow to orange, pink and red. Small berries may form after flowering, which can be pruned off to encourage more blooms. The berries are toxic and may cause vomiting, diarrhea, dilated pupils, and/or labored respiration if ingested. The leaves are rough, and there are tiny spines on the stems, so you may want to wear gloves and long sleeves when planting or pruning these plants. Exposure to bare skin may cause minor contact dermatitis, which usually lasts less than an hour.

Purple Angelonia and orange Lantana in a flower bed.
© 2019 Myatt Landscaping Concepts, Inc.
Yellow Lantana in a mixed planter.
© 2019 Myatt Landscaping Concepts, Inc.

#TeachingTuesday: Southern Magnolia

You can’t get much more southern than a southern magnolia (Magnolia grandiflora)! From the enormous, iconic flowers with their heavy, summery scent to the glossy evergreen leaves that look stunning in every season, it’s no wonder these trees are a classic staple of southern gardens and landscapes. Some of my fondest childhood memories are of visiting my grandparents in Georgia and climbing the large southern magnolia next to the carport. As I got older I would help with the leaf raking whenever I visited, because the one downside is they do drop a lot of leaves!

Maintenance

Southern magnolias are not too difficult to grow as long as the soil moisture level is not too wet or too dry. The challenges with growing these beautiful trees are mainly managing the area beneath the tree and the leaf drop. The dense canopy creates deep shade, and the shallow roots compete for water and nutrients, so it’s very difficult to grow anything underneath an evergreen magnolia. One option is to simply install mulch over the soil underneath the drip line (the widest part of the canopy), or if it’s in a less manicured area, allow the leaves that drop to form a natural mulch layer.

Be prepared for the extra leaf removal work, because the leaves do drop in the spring and the fall. You may want to avoid planting these trees in locations where heavy leaf fall would be annoying to you, such as near a pool, patio, or outdoor kitchen area.

A large old southern magnolia at Duke Gardens. Notice how the leaves are allowed to drop naturally beneath the branches, and the grass ends at the drip line.

ID Tips

  • Leaves are large, broad, elliptical, leathery, and evergreen.
  • Leaves usually have dense brown fuzz (pubescence) on the undersides.
  • The flowers are very large, with white petals and a large cone where seeds are produced in the middle.
  • The flowers are heavily scented and can be smelled from quite a distance! It can be overpowering.
  • After the flowers fade, bright red seeds pop out of the brown fuzzy cones, and the cones later drop onto the ground with the leaves.
Note the brown fuzzy backs of the leaves.

#TeachingTuesday: Cephalotaxus, Japanese Plum Yew

Cephalotaxus harringtonia ‘Pedunculata’
Photo credit: Maryann Debski
JCRA Photo Collection

Today our crews reviewed an interesting evergreen shrub, Cephalotaxus harringtonia, or the Japanese plum yew. Although it has a similar name and similar appearance, it is not the same thing as true yews, which are in the Taxus genus. These shrubs are much more tolerant of the hot, humid summers of the south than the English and Japanese Taxus species. They are also shade tolerant and deer resistant, so all they really need is some protection from drying winter winds and a well-drained site.

Japanese plum yews are highly valued for their deep green evergreen foliage and slow growth rate, meaning they are very low maintenance. It’s hard to name another evergreen shrub so versatile. Their graceful arching branches need not be pruned much at all, and there are several cultivars that exhibit specific growth habits for different applications, such as ‘Prostrata’ for a low, spreading shrub or ‘Fastigiata’ for an upright columnar shrub, great for low- to medium-height hedges. ‘Duke Gardens’ is another well-known cultivar, developed right here in NC at Sarah P. Duke Gardens in Durham (420 Anderson St, Durham, NC 27708). You can see the original plants in the Terraces above the koi pond. To see a collection of several different types of Cephalotaxus, visit the JC Raulston Arboretum at NC State (4415 Beryl Rd, Raleigh, NC 27606).

ID Tips

  • The leaves are long, flat, and linear with pointed tips, arranged spirally around the stems, in two planes, forming a distinct V-shaped trough.
  • On C. harringtonia ‘Fastigiata,’ rather than appearing in two flat planes, the leaves along the stem will show a bottlebrush effect, and will start small, and gradually get larger, then become small again and repeat.
  • On the underside of the leaves, there are two grayish bands.
  • These shrubs do not produce cones, but rather “arils” which are naked seeds, an evolutionary step between cones and actual fruit. There is a fleshy covering over the seed that is open at the bottom, and is shaped somewhat like an olive and is brown to reddish brown in color.
  • The arils and leaves are toxic if ingested, but are safe to handle.
Cephalotaxus harringtonia ‘Duke Gardens’
Photo credit: Mark Weathington
JCRA Photo Collection

#TeachingTuesday: Peonies!

Paeonia lactiflora
Photo credit: Debra Singer-Harter
JCRA Photo Collection

What gorgeous weather we had today, after all those storms on Monday! Today we reviewed one of the showiest garden plants with our crews, the peony (Paeonia sp.). Peonies bloom in mid- to late spring, and winter chilling is required in order for them to bloom, so they do not perform well in the deep south. Luckily in NC, we tend to get more chilling hours than many other southern states. Peonies can be very long-lived, and may be passed down like family heirlooms through generations of gardeners. I (Caitlin) knew a lady in Alexandria, VA, who said that her peony was over 113 years old, and had been passed down by her great grandmother. What a beautiful way to keep memories alive.

Peonies are generally used as flowering specimens in borders, perennial gardens, and cut flower gardens. For optimal growth, they require at least 6 hours of sun exposure and a well-drained soil. Botrytis blight and leaf blotch are the most common disease problems, so make sure there is adequate air circulation around your plants to help prevent these fungal infections. Japanese beetles or scale insects can sometimes cause issues as well. You may notice ants on your peonies because they are attracted to the sap excreted by the flower buds, but they will not damage the plants.

Maintenance Tips

  • Fertilize peonies in the spring when stems are 2-3 inches high, using a low nitrogen complete fertilizer. 5-10-5 or 5-10-10 would be appropriate choices.
  • Peonies are sensitive and easily burned, so do not allow fertilizer or uncomposted manure to come in contact with the plant stems.
  • Remove seed heads after flowering is finished to encourage large flowers the next year.
  • Understand the difference between tree peonies and herbaceous peonies. Herbaceous peonies go dormant in the winter and grow back from an underground crown, but tree peonies are shrubs. Herbaceous peonies can be cut back in the winter, but NEVER cut back a tree peony–it won’t grow back.
Paeonia suffruticosa ‘Shimadajin’
Photo credit: Maryann

Why isn’t my peony blooming?

There are many factors that may prevent a peony from blooming. Investigate to see which of the problems listed below might be causing the problem in your case.

  • The crown may be planted too deeply. The tips of the eyes (dormant buds) should be no deeper than 1 inch below the soil surface. Carefully dig up and replant at a shallower depth during late fall.
  • The plant may be too young. Peonies don’t generally bloom for at least the first three years after planting. Be patient!
  • The plant may have received too much nitrogen, which stimulates vegetative growth at the expense of floral production. Stop fertilizing for a year or two, and make sure you are using a low nitrogen fertilizer (the first number should 5 or less), and that you are applying the correct rate.
  • The plant may be located in an area that is too shady. Make sure the plant is getting at least 6 hours of full sunlight per day during the growing season, or move it to a new location in late fall.
  • If the peony is too crowded, it may not bloom. Make sure there is an adequate amount of space, or you may need to do some transplanting.
  • Nutrient deficiency can also cause a peony to not flower, but if this was the problem there would likely be other signs too, such as discoloration of the foliage (yellowing or reddening). Low nitrogen fertilizer or compost would solve the problem.
  • Insect or disease pressure could cause a peony to not flower, or in the case of Botrytis, the flower buds may drop off without opening. You will see clear signs if this is the problem. Make sure there is adequate air circulation around the plant.
  • Late freezes can kill the immature flower buds. Cover your plants in the afternoon or early evening to trap warm air before a late freeze is predicted, and take off the covers first things in the morning (large sheets work well for this).
Paeonia ‘Bartzella’ – Emerging in spring
Paeonia ‘Bartzella’ – In full bloom
Photo credit: Susan Baily
JCRA Photo Collection