Roses pt. 4- Invasive Introductions to the United States

Rosa multiflora. David G. Smith. 2009. http://www.discoverlife.org.

Roses are a gardener’s delight most of the time. What’s not to love about the beautiful flowers and heavenly scent? Maybe the thorns are a bit much, but every rose must have its thorn right? Well, some roses are a thorn in our side as horticulturalists, landscapers, and conservationists. Unfortunately, some roses have gone on to escape cultivation by throttling the underbrush of the countryside, particularly in the Southeastern United States. Their thorny nature and sprawling habit make them hard to pull out of unwanted places, and only come back when having been pulled out. Yes, unfortunately its true, some roses are a NIGHTMARE!

Some will never find anything bad to say about roses, but I for one have a problem with R. multiflora. The multiflora rose is a thorn in my side, as I often come across them having to weed garden beds. While the multiflora rose is not the worst offender when it comes to thorns, they grow relatively quickly. The plant is unassuming at first, being a weedy, thorny, sprawling rose, growing to be ten feet tall by fifteen feet wide at their largest. The rose flowers come in corymbs of small white single flowers or pink multiple flowers (this is another variety actually- v. cathayensis.) The plant spreads by its abundant seeds in the red hips that adorn the plant throughout the winter- birds love to eat them and spread them in their feces.

This rose was introduced from Asia in an environment quite like that of the Southeastern United States. Introduced as a conversation measure for erosion control, it quickly spread to being everywhere in the disturbed parts of the lower Appalachians. It is considered now a noxious weed, unfit for cultivation in its range. The flowers fragrance is not worth saving, as its too light to appreciate otherwise, and makes no impact when grown in cluster on the nose or the eye.

Rosa laevigata. Daderot. 22 April 2011. Wikimedia Commons.

Another rose that has been introduced, but is not as hated, is the Cherokee rose. This rose is from farther south in Asia, closer to Southern China, Taiwan, and Vietnam, giving it a limited hardiness range in the United States (generally to zone 8.) Where this evergreen climbing rose will grow, it will grow in abundance, but it is not beyond salvation. This rose has a very unique fragrance for a rose, almost as sweet as Gardenia, and makes for an excellent climbing rose on trellises. This rose tends to bloom white, with large identifiable blooms from a ways away, and nice yellow stamens, making for a brilliant impact.

This rose has been linked to the Trail of Tears in U.S. history, and more recently, has been featured in the Walking Dead. It is the state flower of Georgia (although if we were going to make any introduced flower the state flower of Georgia it should be the Crepe Myrtle, but I digress…) where it grows nicely.

Truth by told, many of the roses introduced could be invasive to the U.S. in one place or another. One example is the dog rose, R. canina of Europe, another favorite of English poets, as it grew very nearly everywhere in the countryside in its day. Its invasive to cooler parts of the Eastern U.S., but is not as noxious as the others above. This particular rose also has a nice rose scent, and its hips make excellent jams. Hopefully, the next post will wrap up roses as I do wild ones to the United States, then its on to lillies!

 

Roses pt. 3- Sweet Briars

Rosa rubiginosa. 23 February 2014. HitroMilanese. Wikimedia Commons.

While roses are known for the sweet scent of their flowers, some are also known for their scented leaves and stipules among other things. Many roses in a sense do also have fragrant parts besides their flowers, but none more so than sweet briars, known for their sweetly-scented foliage. Chief among these is R. rubiginosa, with its apple scented foliage that disperses particularly well in rain. These rampant growers are beloved by poets, particularly Keats (thank you again to Wilder for pointing that out in her work, The Fragrant Path.) This rose is native to Europe and Western Asia, and its hips are used to make an herbal tea known for its high Vitamin C amounts. Lastly, This rose is invasive to the milder parts of the Southern Hemisphere.

Another fragrant sweet briar is R. ecae from Central Asia. Its a shrubby rose growing to six feet, with small yellow flowers. It is not cultivated outside its native range often.

Fragrant Hydrangeas

Hydrangea quercifolia. Anne Norman. Wikimedia Commons.

Summer is right around the corner, and in my neck of the woods, summer is incomplete without Hydrangeas everywhere! Hydrangeas are native to the warm temperate and subtropical forests of East Asia and the United States, and there are many wild varieties. Garden hydrangeas are normally grown for colorful, big, bushy blooms, particularly seen in H. macrophylla. Who doesn’t love the big bushy blue to pink and all colors in between blooms? Your nose. That’s right! Those Hydrangeas you  normally love are not the fragrant ones in most cases.

The more colorful Hydrangeas are the Asian varieties, but in a horticultural world twist- the fragrant ones are the American varieties! Normally its the other way around (viburnum and osmanthus come to mind here) but the mold must always break somewhere. The American genus leading the way on fragrance is oakleaf hydrangea, H. quercifolia.The similar H. radiata and H. cinerea are also similarly fragrant.

Oakleaf hydrangeas are native to the Southeast, and grow in the Piedmont and coastal plains. Oakleaf hydrangeas are not modest plants, one specimen at the University of Kentucky arboretum was eight feet high with a ten foot spread, and that still isn’t the largest out there! They grow to be nearly thirty feet in the wild, and have a large open crown. In the wild, they often form large thickets, as the plant spreads via underground stems (stolons) and have identifiably cinnamon-brown, peeling bark. The large five-lobed leaves look similar to oaks (hence the oak leaf) but much larger- up to eight inches in length, and turn a brilliant red in fall. In summer (May-September), these Hydrangeas bloom with an odd spiked display- flowers are small ‘spiky balls’ in between petaled bracts that appear as the ‘flowers.’ The whole spike is nearly a foot long, and ages from white to pink to brown, where they will hang on all winter as the lower leaves drop off.

The scent is very interesting in these plants. Its brought out best by heat and humidity, and almost reminds me of a type of glue that was commonly used when I was a child (It was a bluish glue with glitter I assume to make it kid friendly?) Anyways, its a smell that is sour but extremely sweet, bordering on overkill, and cloys quickly en masse. Its not indolent like others, but cloying like privets are. I love them, but its not a scent I want in my garden come evening if that makes sense.

These plants are great in a forest garden or under planting for trees, and there are many cultivars (including dwarfs) available. I would avoid hot sun as these plants cannot handle drought and must be well watered and kept from wilting. Lastly, they are hardy in zones 6-9, and marginally hardy in zone 5.

Hydrangea radiata. Hectonichus. 29 June 2012. Wikimedia Commons.

H. radiata and H. cinerea are also native to the Southeast, but H. radiata is limited to the Southern Appalachians and H. cinerea spreads to the Ozarks. H. radiata is called the silverleaf hydrangea for its leaves being silvery on the undersides, and H. cinerea is called the grey hydrangea likewise for its grey pubescent leaf underside. The two both grow to be ten feet tall and have flowers in corymbs, blooming in June to July. Both plants can be cultivated in gardens, but silverleaf hydrangea is the more difficult of the two, as it requires cooler temperatures and more moisture than grey hydrangea, although it is showier.

Summer Blooming Magnolias

Magnolia grandiflora. DavetheMage. Wikimedia Commons.

Nothing says summer more than the scent of the summer blooming Magnolias! These trees are a staple of the American South, and are culturally significant to the region, being the source of many literary references, movie references, and perfume and candle scents. M. grandiflora has large flowers (up to one foot long) that are very fragrant of lemon, with a musky to rank undercurrent. Its a very endearing scent nonetheless, and a neighborhood bathed in the scent on a humid evening is one of the finer scents of the horticultural world.

The tree grows over a large region in the Southern United States by the coast. The larger trees are hardy to zone 8, but many cultivars are available on the market hardy to zone 6, like Bracken Brown and Little Gem, which happen to be minis. I’ve noticed many of these small cultivars growing here in my home of Lexington, Kentucky at a zone of 6b, and some have been known to grow as far north as Cincinnati, Ohio in zone 6a.  The trees are rarely higher than 30 feet in these locations however.

The flowering is over a wide period, from mid-May to September. The largest bloom occurs in June, but many trees will have a smattering of blooms throughout the season. The largest trees will grow to be up to 100 feet, but they are more common topping out in the 80 foot range. These evergreen trees are native to the moist forests and swamps of the Coastal plain, but can grow in a variety of conditions as long as they get water during establishment. Be warned that in marginally hardy areas, one good cold snap with wet soil conditions is enough to take out these trees. They are also intolerant of ice storms, due to their large evergreen leaves, and the branches will snap, as they did this past year in many places across the south.

Magnolia sieboldii. Daniel Mosquin. http://www.botanicalgarden.ubc.ca.

M. sieboldii has a bloom period much like the Southern Magnolia, blooming in late May and early June heavily, but continuing throughout the season with a small smattering of blooms. Its an East Asian native, and is national flower of North Korea.  It is a smaller growing tree, only up to 30 feet, and often only making it to large bush size. The flowers are 4-5 inches across, with striking red stamens, and a sweet smell. It is deciduous, but has nice large leaves in either case. Its a perfect small garden and courtyard specimen.

M. sieboldii is more particular about growing conditions, but it is hardier than the Southern Magnolia, and able to grow better in Northern gardens, as long as its not given a southern exposure which encourages earlier bloom. Its a rarer specimen, and I have never come across any in bloom in my home state of Kentucky.

Lastly, I apologize for the lack of posts on this blog. I am rather busy of late, and exhausted most nights. Please forgive me for my lack of reliable posts! Also, if I have not talked about a certain fragrant plant, feel free to give me suggestions for plants to detail!

Orange Jasmine

Murraya paniculata. http://www.toptropicals.com.

While May is all about Northern bloomers, this one is, and has been, gracing southern gardens for some time. In pots, this plant blooms during warmer months indoors, and is an ever bloomer in tropical locales. However, starting in April and going through June is the typical heaviest bloom period, where an entire greenhouse and/or garden is bathed in the delicious scent. Another Southeast Asian native, this plant is related to Citrus, where it gets half of its epitaph from. The shrub has a look and scent similar to Citrus, but grows smaller and makes for an excellent hedge. It has pinnate leaves, setting it apart from Citrus as well as smaller, densely clustered flowers.  It also has the ability to grow in any soil and climate conditions except for extreme drought and is only hardy to zone 10.

Orange Jasmine or Orange Jessamine grows all is planted all over the tropics and in several greenhouses. My own town has a large indoor collection at Pemberton’s. Murraya paniculata has a scent similar to orange blossoms, but also has the ability to blend in with season bloomers. I’ve noticed them smelling just like Easter Lilies when blooming near the holiday, and like Hyacinths in spring, but otherwise a very warm, sweet, orange blossom essence. Its a very interesting phenomenon, and is very generous with its scent no matter where it happens to grow. It also sets inedible red fruits after its bloom that can be used to propagate the plants, and makes for a good food source for birds.

Related to M. paniculata is M. koenigii, called Curry tree for its curry scented leaves. The fresh leaves are used in curry dishes and the oil from the seeds of the fruits in aromatherapy. It is also a tropical landscape plant, although the flowers are not as impressive or fragrant. The plants are also known for their medical benefits due to their chemical compounds.

I continue to be on backlog for detailing fragrances, just as I continue to be on backlog with plantings at my job. Gotta love this time of year!