After the lazy days of August, September can seem like the busiest month of the year. So many neglected chores, both inside and out, await attention. For a lot of us, the summer containers gracing our entryways need a makeover. You can buy a pot of mums or……
You can plant succulents.
Followers of this blog must know by now that I am a big succulent fan, and even after a wet and extremely humid spell, I can still say the succulents planters we did up earlier not only still look sweet, they are going to get better as the night temperatures become chilly. Cool night temperature bring out deep and rosy tones in the blue, olive and bronze foliage colors of the many non hardy succulents. Many tender forms such as Echeveria ‘Black Prince‘ and Senecio ‘Blazing Glory’, begin to bloom as do many hardy species of Sedum such as S cauticola ’Lidakense’ , ‘Turkish Delight’ and ‘Dazzleberry’.
Succulents are mix and match plants. Of course, they all like the same sandy, well drained soil mix, and the colors all work well together. I’d like to add that the most interesting combinations include plants which have light, medium and dark tones. In this pair of planters, I’ve used Euphorbia tirucalli var rosea, commonly called ‘Sticks on Fire’ (guess how it got its common name) for height, the blue gray rosettes of Senecio ‘Blazing Glory’, a coppery orange tinted Sedum nussbaumeranum, the soft yellow Sedum makinoi ‘Ogon’ and an olive tinted Sedum tetractinum to spill over the sides. Tucked in for added dark tones is Sedeveria ‘Jetbeads’.
1.When you group succulents together you can pack them in quite close together. They do not need a lot of nourishment nor water, and they don’t grow very fast.
2.The selections that are not hardy in your area will need protection when temperatures dip below freezing, and here we sometimes get a really cold night in late October, followed by a spell of Indian summer. Either move the pot inside if a frost is in the forecast, or cover with a large tarp or blanket.
3. Once it becomes apparent that temperatures will be below freezing at night on a regular basis, bring your container into a frost free area that gets bright sunlight. If your container is too big to bring indoors, dig out the specimen plants you would like to keep and pot them up in a sandy quick draining soil mix. I plan to do a blog post about what to do about wintering over succulents in a month or so.
Related Blog Posts
Come on…how about a little imagination? There’s more to fall container gardening than a pot of mums which are already on display at the supermarket entrance. I can allow that some folks love their tidy appearance and that these almost perfect balls provide an immediate color fix, but really, do we all have to be that predictable? Of course not.
Here in Massachusetts, I like to pot up end of summer/fall containers in late August to give plants a chance to kick in with some growth before cooler temperatures and shorter days slow things down. I had this lovely turquoise pot begging me to fill it, so I selected colors that would sing, still nodding to late summer, but with approaching autumn hues.
The winter hardy perennials used here include: Heuchera ‘Southern Comfort‘ and Acorus gramineus ‘Ogon’. The Hedera ‘Amber Waves’ and the Coprosma repens ‘Multicolor’ can take temperatures in the 20′s without being fazed, and the Plectranthus ‘Velvet Elvis’ with its dark green/purple foliage will star as the flowers begin to show off in September and October. Yes it could get frosted on a really chilly night, but should one be forecasted while it is still showing off, cover the planter with a large tarp or move inside for the night.
I think I know the reason why few people grow this easy care, refreshing native plant, commonly called Prairie Baby’s Breath: plants, even young seedlings, transplant poorly. The happiest plants have planted themselves, like this clump that adorns our front walk entry right now; it was sown in situ. Of course, you need to have a mother plant nearby to have these babies come up on their on accord, and that’s a “chicken or the egg” dilemma. We always have a few potted plants here at Avant Gardens but because they usually look weak and spindly, they are not an easy sell….unless you happen to visit our nursery and gardens in August. Now, everyone marvels at this “different baby’s breath” when they pass by.
Once established, Euphorbia corollata asks for little but sunshine and well drained soil. It begins to bloom heavily in mid July and carries the show through the month of August. I haven’t tried it as a cut flower, (it is a spurge and has that milky sap), but maybe I should experiment with sealing the stems with a flame, which will prevent that sap from poisoning the vase water. Perhaps it would be prudent to stress that some people are very sensitive to Euphorbia sap and can get serious skin irritations when exposed to it. Fortunately for me it has never been a problem.
Euphorbia corollata is hardy in zones 4-7. We planted it in our gardens more than 20 years ago, and it is still there, a testimonial to it’s longevity, often popping in new spots, especially well drained pockets. Should it sow where you don’t want it, just pull it out. In addition to being quite attractive to beneficial insects, such as bees and wasps, it isn’t a plant deer or rabbits will likely munch on, since it is poisonous if ingested.
…New Selections for Cutting
It’s easy to be seduced by catalog images. I was when I saw some of the recent Phlox paniculata being bred in Holland. The inflorescence were distinct from our more familiar forms: the florets were smaller, slightly curled and edged in contrasting colors.
Last year I planted Phlox paniculata ‘Sherbert Blend’. I wasn’t sure what to make of it at first. The panicles were small, and the florets appeared pale pink with a faint cream edge in the garden, although the images in the catalog promised me a warmer, pink shade. I shrugged the color discrepancy off, thinking this may be due to weather or soil conditions, or maybe the plants would show their true colors with maturity. I have since discovered that this Phlox’s color range changes with the time of day, and is true especially in early morning light.
This year I tried 2 other selections: Phlox paniculata ‘Jade’, with lovely white florets rimmed in celadon green, and Phlox paniculata ‘Aureole’ or ‘Neon Aureole’ which has tight clusters of bright fuchsia florets, edged in white and green. Our supplier’s catalog described plants as being only 16-20″ tall, but already I’m observing stems in the 24-30″ range. So far, mildew has not been a problem, and plants have set side shoots for rebloom quickly, once the first main stems have been cut. All emit a slight, old fashioned, sweet fragrance.
Grow these Phlox in full sun, in average garden soil and provide good air circulation. Blooming begins in July and carries on into August. Although these new Phlox make fine border plants, they have are more subtle than the big panicled forms with huge florets. I’m considering moving my plants into a new bed I’m creating just for cutting, since I know the floral display in the garden will be sacrificed for many more summer bouquets.
Here are some closeup portraits of each Phlox used in the pictured bouquet:
At last, we found an image that displays Lesser Calamint, Calamintha nepeta ssp. nepeta , in a flattering light. Perhaps that’s why more people don’t grow it: it doesn’t always photograph well, and it’s not in bloom when everyone is plant shopping in April and May. It has been one of our “go to” plants when designing sunny gardens for years. Here’s why.
Calamintha nepeta ssp. nepeta has grown well in our garden for the past 18 years. Yes, the same specimens, planted in 1995, return each year true to form. In spring they present as tidy little subshrubs (no, it does not spread by runners) with mint scented, slightly shiny leaves. In July (June in warmer zones) sturdy 18″ stems bearing racemes of airy blue tinted white flowers appear, creating a cloud like effect for the front of the border and accenting any plant around it, and it is especially complimentary to roses. The blossoming continues into October, when the flowers take on blue tones with cooler temperatures. Calamintha nepeta ssp. nepeta is a primo plant for attracting bees, butterflies and beneficial insects. This form of Lesser Calamint has rarely self sown in our gardens, unlike the very similar Calamintha nepeta ‘White Cloud’, which seems to happily self sow. You might like having babies, or not. You decide.
As mentioned before, this is a reliable perennial (18 years and still going strong) for us here in southern New England. Calamintha nepeta ssp. nepeta performs well whether we are having a hot dry summer or a cool moist one. It likes a soil that is well drained, but does not need or want lots of fertilizer. I know it will be this reliable in zones 5-7, but would be interested in hearing if folks are growing it successfully in zones 8 and 9. Its tidy form and endless flowering means it can be combined with so many other plants, depending on your color scheme, but consider using it with Asclepias tuberosa, Sedum ‘Maestro’, Echinacea ‘Fatal Attraction’ or Caryopteris for strong summer interest.
Each year in recent history, I have been documenting with images some of the containers I plant up here at Avant Gardens. I like to take images within a few weeks of planting, and then again in September. The September shots will show which containers still look incredible. Plant selections with minimal care requirements are used in each of these groupings. Below, you will find combinations for shade, part shade and sun.
For shade/pt. shade:
Begonia ‘MK Elegance’ with Hedera ‘Little Diamond’
for part shade/sun:
Fan favorite: Classic Bowl with Mixed Succulents
Senecio cylindricus dominates this large basalt bowl (22″)
My favorite pot with Aeonium, Euphorbia and Echeveria
The vertical garden was planted in late March, and now little Delosperma ‘Firespinner’ is beginning to flower
Echeveria ‘Afterglow’ with Phormium ‘Pink Stripe’ and Dichondra
You can mix succulents with other plants which don’t mind dry conditions (like the combination above). Even though we have had an unusually large amount of rainfall lately in the northeast , all of our succulents and begonias are still thriving because we use a sandy well drained soil mix. If you use a regular or rich potting soil, you chance disappointment from plants rotting away.
Check back in September, when I post the “after” shots!
It was a hot summer afternoon in mid July. I was alone at the nursery, watering, when an elderly woman appeared out of no where. I always keep my ears perked for cars pulling into the gravel driveway, but hadn’t heard a thing. The woman asked me, in a very aristocratic tone, if I grew Acanthus. I chuckled and said that we had tried but it had been a disappointment , struggling to emerge each year, only sending up a leaf or two.
She suggested we grow it in a hot sunny spot , and be patient. I thanked her for her advice, and continued watering while she seemed to browse. Less than a minute later I looked up to see if she had questions or needed help, and she was nowhere to be seen. Even a spry teenager would have had to bolt to reach the exit in such short a time. I walked up to the driveway to the road but there was no one and no car in sight. Hmmm…..
A few months later, an autumn storm felled a large tree. The following year, a patch of robust Acanthus foliage emerged in a spot now baked from the hot sun; the felled tree had shaded the spot more than we thought. By late June we were seeing our first blossoms. I now think of that mysterious woman and her advice whenever the Acanthus come into bloom.
The Acanthus are putting on a great show right now with bold dark green leaves and sturdy 3’ spires of hooded lavender flowers. They are loving the hot spot by our stone wall This show will carry on into late July. We’ll deadhead the spent flowers, so the foliage will continue to look good for the remainder of the season.
Some info for northern gardeners. The hardiest species are Acanthus spinosus and Acanthus hungaricus., hardy to -10 degrees. (zone 6a) The two are often confused, but upon close observation spinosus will display a more sharply serrated leaf with spiny tips. There is also a hardy selection, ‘Morning Candle’, which is a hybrid of A. hungaricus x A. mollis, and offers the hardiness of the former, but with white hooded flowers. Acanthus spread by creeping rootstock, and even bits of roots left in the soil will regenerate into new plants over time. A mass display of Acanthus is an impressive sight.
Looking for a new perennial to brighten up a shady spot? Consider this variegated form of Peuce, also known as the other Masterwort, (no, it’s not Astrantia). Peucedanum ostruthium ‘Daphnis’ is a recent introduction from France, and we’ve stumped a number of plant pros with its identity. At first glance it looks like a refined form of Variegated Aegopodium (Goutweed), and as people shudder with horror, we calm their fears immediately. Peucedanum forms tidy clumps, and is not invasive. It does have lovely cream, gray and green foliage, grows 8-10″ tall and spreads to about 15-18″. Flowers, born on 15-20″ stems in early summer resemble Queen Anne’s Lace, and are lovely cut.
Peucedanum ostruthium ‘Daphnis’ is easy to grow, preferring an average to moist soil in partial to full shade, but will take even more sun in moist settings. We know it is hardy in zones 5-9, but it may in fact prove even more cold tolerant. It is an attractive foil for Ferns, Hakonechloa macra or dark green Hosta.
Over the past few years there’s been a lot of buzz about vertical gardens. Patrick Blanc, the French botanist, has created some amazing spaces on a large scale, using a wide variety of plants to transform whole buildings. Of course there is more to his vertical gardens than meets the eye. His crews construct huge freestanding armatures with built in irrigation systems, which is a necessity for the types of plants he uses. A big concern for me concerning his designs is plant hardiness. This is not a problem with his indoor or tropical climate gardens, but how does one sustain these plantings in northern climates without huge plant losses?
We considered how we could turn this concept of using vertical space into something more practical that most gardeners could implement on their own. What type of plantings would not need an irrigation system built in? Chris and I decided we could create sustainable vertical gardens using rot resistant wood for the boxes and plant them with drought tolerant succulents which will survive quite well without lots of water. They hold up well the entire growing season on a sun filled south facing wall, and could be taken down for the winter. The boxes could either be brought indoors if they were planted with tender succulents, or if planted with hardy succulents, laid on the ground, covered with a winter mulch. Here’s a quick how to:
Rot resistant wood such as cedar or mahogany.We used 1 x 4′s for the box and frame, and 1 x 8′s for the backing.
Wire mesh with 1-2″ openings
Well drained succulent potting soil and assorted low growing succulents
Decide what your dimensions will be and build your box. Fill with a well-drained succulent potting soil.
Lay a wire grid over the soil. This will help secure plants in place while they root in.
I always start by first placing the showiest plants. You may need to cut wider openings in the wire mesh to allow for bigger roots.
I then fill in around my focal point plants with other low growing succulents. Be careful not to select plants that tend to grow tall.
Your best choices are plants which are going to stay under 4″, especially ones that stay under 2″.
After the planting is done, you can attach the frame.
Plants will establish good root systems in 6-8 weeks, or even more quickly in warm weather. Some plants may overtake their neighbors, so a little trimming back could be necessary. You may also want to tuck in a cutting here and there to refine your “painting” as it grows out.
Watering can be done by spraying the plants with a hose early in the day (be careful not to water when the sun is strong or you will get water scars on the foliage). Or, remove the box from its mount, lie flat and give a good soak. Succulents are not plants that need a lot of fertilization, but if you think it’s necessary you can use a diluted fish emulsion to give them an occasional boost.
Space is limited.
I often like to tempt you with plants which I suspect you may be unfamiliar with, but a walk about the garden convinced me to laud praise on our garden stalwarts. In particular I’d like to reacquaint you with my old perennial favorite, Baptisia, and its recent reincarnations.
Baptisia, commonly known as False Indigo or False Lupine, was one of the perennials we planted in our first garden 25 years ago, and that same B. australis, introduced as a young seedling, still surges forth each spring with vigor and good looks. Baptisia is not a only long lived plant, it is also one of the first perennials which add height to the late spring border, shooting up to and eventually forming clumps of 3’ or more. The early size factor adds greatly to it’s value. The flowers are displayed on showy spires and resemble lupines. It is a great compliment to the other late spring stars: Peonies, Iris, Euphorbia and late bulbs like Allium.
The most common species you’ll encounter is B. australis, with typically violet blue flowers and a height of 3-4’ and equal width. Other species you may commonly encounter include B. alba, (with white flowers) and B. sphaerocarpa (yellow), and to some extent B. bracteata. In recent years hybrids have been made crossing the species, alternating host and pollen plants. Ron Gardner introduced ‘Carolina Moonlight’ after successfully crossing B. alba and B. sphaerocarpa in 2002. Jim Ault of the Chicago Garden has developed a number of great cultivars by crossing B. australis and sphaerocarpa resulting in named forms B. ‘Solar Flare’, ‘Twilight’, and ‘Midnight Prairie Blues’. Hans Hansen has developed more crosses are becoming available such as ‘Lemon Meringue’ and ‘Dutch Chocolate’.
A form we grow in our gardens which always draws comment for it’s compact habit is Baptisia australis var minor. It forms a low 2”mound of dense blue green foliage with typical large blue violet flowers, but long after the flowers fade, B. australis var minor shows off with its tidy appearance . Another excellent but slow growing form is a selection made by Brian Megowan of the legendary Blue Meadow Farm: B. ‘Esther’, with her white flowers born on dusky slate stems. We’re rooting stem cuttings of her now, in hopes of having young plants for sale next spring.
Some things to note. Baptisia are prairie plants and like a sunny well drained soil. Baptisia australis is the hardiest of the group, tolerating cold zone 3 winters. Baptisia alba and sphaerocarpa are hardy through zone 5. The hybrids seem to fall right in the middle with hardiness tolerance of zones 4-9. Baptisia species can be grown from seed, but her clones are vegetatively propagated. Baptisia develop deep tap roots, so division isn’t easy, although it can be done, but expect some die back and a slow recovery.