Love Roses but hate diseases: Rugosa Rose for you

Rugosa Rose

If you love roses but don’t want to fuss with tender, disease-prone garden roses, rugosa rose is for you. This dense-growing, wide-spreading shrub rose is exceedingly cold hardy and disease resistant. It produces loads of beautiful, fragrant, rosy violet flowers in early summer and sporadically in late summer and early fall. Hybrid cultivars of rugosa rose have white, light pink, deep pink, and purplish red flowers.

Common name: Rugosa rose or Japanese rose

Botanical name: Rosa rugosa

Plant type: Deciduous shrub

Zones: 2 to 9

Height: 3 to 8 feet

Width: 3 to 8 feet

Family: Rosaceae, rose family

Growing conditions

Sun: Full sun.

Soil: Prefers well-drained soil with ample organic matter but tolerates a range of soil types, including clay and sand. Slightly acidic soil pH is best.

Moisture: Consistent moisture is preferable, but rugosa rose has fairly good drought tolerance.

Care

Mulch: None, or a 1- to 2-inch layer of organic mulch such as small wood chips, composted leaves, or cocoa bean hulls.

Pruning: Rugosa roses take well to pruning, though their thorny stems can make it a daunting experience for the gardener. Prune in spring to reduce height.

Fertiliser: Apply a balanced fertiliser once or twice during the growing season.

Propagation

• You can grow species from seeds. Seeds require a cold stratification period of three to four months. Sow seeds outdoors in the fall, or place the seeds in a plastic bag with some slightly damp sphagnum peat moss and store in the refrigerator for three to four months. Then sow seeds indoors under lights.

• Propagate cultivars from softwood cuttings taken in mid- to late summer. Treat with a rooting hormone.

Pests and diseases

• Resistant to rose diseases such as blackspot and powdery mildew.

• Aphids, mossy rose gall (caused by a small wasp), and Japanese beetles may affect rugosa rose.

Garden notes

• Rugosa rose is amazingly salt tolerant. It has naturalised along sandy beach areas in New England, where it is sometimes called “saltspray rose.” It also tolerates road salt that is applied in cold climates.

• Harvest the large, red-orange hips to make jelly. These large, colourful hips give this rose one of its other common names-beach tomato.

• Mix rugosa roses with other roses, flowering shrubs, small evergreens, and perennials. Or use them as a low hedge or foundation planting.

All in the family

• Rugosa rose is used in shrub-rose breeding projects because its genes contribute cold tolerance and disease resistance to the resulting hybrids.

• Rugosa roses originated in Japan, Northern China, and Korea, but they have naturalised in a number of places in North America.

• The rose family is a huge and diverse group of plants that includes many ornamental and food-producing plants, including apples, peaches, cherries, raspberries, mountain ash (Sorbus), hawthorns (Crataegus), spireas, and, of course, roses.

Some of the best flowering house plants

Everyone enjoys blooming plants indoors, but if you live where the growing season is short, an indoor garden is an absolute necessity. In addition to tropical foliage plants, I depend on plants that produce flowers reliably year after year to brighten up my home throughout the year. And what a joy those flowers are, particularly in winter and early spring when the view out the window is still bleak.

Some blooming houseplants love bright sun, but others thrive in filtered bright light. A few even bloom in relatively low light. Light is not the only variable that affects blooming, though. Soil moisture, fertilising, and temperatures play a role, too.

Here are some favourites that bloom reliably, are easy to care for, and are readily available from garden centres and mail order growers.

Flamingo flower

Anthurium (Anthurium spp.), or flamingo flower, is closely related to the peace lily. It needs similar growing conditions, with one major exception: Anthurium requires more light to bloom well. Mine blooms constantly in a west-facing bay window, with sheer shades lowered in summer to protect it from intense sun.

In recent years, plant breeders have developed new types of anthuriums. You might find one with a curly spadix or unusually colored spathes, some of them quite small. But the most popular plants produce large, waxy, heart-shaped spathes that start out dark pink or red, then turn greenish as they mature. For a long-lasting cut flower, harvest a flower stem and display it in a vase—it won’t hurt the plant.

African violet

Probably the most common of all flowering houseplants, this member of the Gesneriaceae family is a favourite of indoor gardeners. African violets (Saintpaulia hybridus) are easy to grow, which explains their popularity—that, and the beautiful flowers they produce in relatively modest light. There are thousands of cultivars, and the list keeps expanding.

Use a peaty potting mix for African violets. Most garden centres have potting soil and fertiliser labeled specifically for African violets. Water thoroughly whenever the soil surface feels a bit dry, and spill out any excess water that flows through the drain hole. Many insist these plants should be “bottom watered” (allowed to absorb water from a saucer) because their fuzzy leaves are prone to water spots. If you use this technique, water thoroughly from the top every six to eight weeks to flush accumulated salts from the soil. Bottom watering isn’t necessary, though, if you direct water toward the base of the plant and keep its foliage dry.

African violet grows best in bright, filtered light, but will bloom in a north window—though less frequently. It won’t bloom in a dark corner or in intense sunlight. It’s an excellent choice for growing under fluorescent lights, where it often blooms continually. The plant grows best in relatively warm temperatures.

Use a very weak fertiliser solution with every watering, or fertilise at half strength every two or three weeks when the plant is growing actively. Almost any houseplant fertiliser will do, provided it is balanced or has a higher phosphorus than nitrogen percentage.

Cape primrose

An African violet relative, the cape primrose (Streptocarpus spp.) should be grown more often than it is. Its large, velvety blossoms are borne on wiry stems that arch over strap-like, stiff leaves. Flower colors are similar to African violet—deep purple, maroon, blue, white, lavender, and many shades of rose and pink. Its needs are different from African violet in two areas: It requires brighter light year-round and filtered light in summer, and it blooms best when temperatures are on the cool side (50ºF to 65ºF), particularly at night.

When cape primrose gets too scraggly—it’s less tidy and compact than African violet—it’s easy to start new ones from a leaf cutting. Remove a medium-sized leaf and cut it almost in half, lengthwise. Keep the portion that contains the mid-rib, and plant it horizontally in moist potting soil so the mid-rib is buried. Small new plantlets will form all along the mid-rib.

Peace lily

Peace lily (Spathyphyllum spp.), sometimes called white anthurium, is a member of the Araceae family, a large group of plants encompassing some of our best houseplants—Chinese evergreen, philodendron, arrowhead vine, and dieffenbachia. (Jack-in-the-pulpit and calla lilies are also in this family.) Their flowers are minuscule, packed together on an elongated structure called a spadix, with a showier sail-like spathe behind it.

Peace lily does well in low light. It blooms sporadically in a north-facing window or several feet away from brighter exposure, but will bloom year-round in an east-facing window or in bright, filtered light. Flowers (spathes, really) unfurl pure white, then slowly fade to green over many weeks. To encourage more blooming and keep the plant looking its best, remove flower stalks once spathes look greenish.

Keep the potting soil evenly moist, watering thoroughly whenever the surface feels slightly dry. Spill out excess water that flows through the drain hole. Peace lily tolerates low humidity and does best in relatively warm conditions with nights no lower than 62ºF and days up to 80ºF. Fertilise lightly during periods of active growth, which typically lasts from late winter through early autumn.

Wax plant

This old-fashioned vining houseplant (shown above) belongs to the Asclepidaceae (milkweed) family, and it’s often referred to simply as hoya. A slow-growing succulent with plump, leathery leaves, hoya (Hoya carnosa) thrives in bright light and prefers well-drained soil that’s allowed to grow quite dry after watering.

Hoya’s reputation for being slow to bloom is well-deserved. It often takes years of good care before hanging clusters of star-shaped, velvety blossoms develop, but it’s worth the wait. The flowers are not only beautiful, but also delightfully fragrant at night. Flower clusters reappear annually on the same short spurs that hang from hoya’s woody vines. Don’t prune those vines; train them up supports or twist them in big hanging loops.

Keep hoya cool (it can tolerate temperatures in the low 50s without being damaged) and make sure it’s dryer in winter than in spring and summer when it’s growing actively. Fertilize only when it’s putting on new growth, usually from late winter or spring through summer. If you’re lucky, you may see two flushes of bloom each year.

Poinsettia Pointers

Follow our tips and enjoy your poinsettia next holiday season.

After the holidays: Place the poinsettia in a very sunny indoor spot and keep soil barely moist. Fertiliae as package recommends.

March: Trim to 6 to 8 inches tall after its leaves fall. Continue to water and fertiliae.

May: When poinsettia shows strong new growth, repot and bring outdoors. Give plant six to eight hours of sunlight daily. Protect from harsh afternoon sun. Fertiliae weekly.

Mid-July: Trim one-fourth of growing tips to encourage branching. Leave at least 2 to 3 large leaves on each stem. Continue watering and fertiliaing.

Early autumn: Bring indoors when nights fall below 60°F.

October 1 to December 15: Place your poinsettia in complete darkness from 5 p.m. until 8 a.m. in temperatures around 65°F. Any light—even for a moment—will ruin your efforts. Place in a sunny location during the day.

Mid-December: After bracts start to colour, a long night is not as necessary, but keep giving poinsettia six to eight hours of bright sunlight until completely coloured. Then stop fertilising and place the plant in its holiday  location. Your poinsettia may not be quite as lush or bright as those in the nurseries, but it will still be beautiful.

What can I do to make my holiday poinsettia turn red again next year?

After the holidays, continue to grow your poinsettia in a bright, sunny location. Once frost danger has passed, put it outdoors in dappled light or leave it in that sunny spot indoors. Water and fertilise to keep the plant growing actively. Cut it back in early July, leaving several strong stems, but don’t prune after that. If you’ve kept the poinsettia outdoors, wash it carefully before bringing it back into a bright indoor location by mid-September.

Starting around the third week in September, expose the poinsettia to short sunny days and long dark nights to  trigger flower formation. Cover the poinsettia with a dark plastic trash bag or a box, or put it in a closet so it’s completely dark for 12 or 13 hours every night. Uncover it or bring it back to its bright location every morning.   

Continue to water the soil when the surface feels dry, and fertilise at half strength about every six weeks. Within six to eight weeks bracts should begin to turn red again. (Bracts are the colourful, modified leaves that develop around the less showy “true” gold flowers.) Continue to give the plant short, sunny days and long, dark nights until the bracts are coloured fully. Then put the poinsettia in its bright location permanently.

Your poinsettia is unlikely to develop as intense a colour as it did when professionally grown in a greenhouse. It’s fun to give it a try, though, and it’s a great project to work on with a youngster who’s interested in plants.