New Plant of the Day: Cerinthe major

Cerinthe major ‘Purpurascens’
Family: Boraginaceae
Common name: honeywort
Origin: southern Europe, Mediterranean
Zone: 8-10
Size: 2’
Light: Full sun to part shade
Soil: moist, well-drained humus rich soil

I recently received this photograph from an old schoolmate of mine who could not identify it. It took me a little while but I was finally able to identify it as Cerinthe major. This is a new plant to me so I thought I would pass on the information I found.

The plant has thick blue-green leaves with white moddling. Small clusters of 1”-long nodding purple flowers form late summer and attract bees and hummingbirds. The tall stems curve like that of a shrimp, thus it is referred to by some as “shrimp plant”.

Start seeds indoors before spring and transplant outdoors after frost. Many have recorded that this plant self sows quite easily.

When to Plant Fall Blooming Bulbs?

(Crocus speciosus photograph courtesy of Sonja Keohane, all rights reserved.)

Question:
I just wanted to double-check a question about fall flower blooming. For fall-flowering bulbs like Colchicum autumnale, true hardy crocus varieties, and hardy cyclamen, can one plant now to get fall flowers because the flowers come up on the bulbs so quickly. Is this correct?


Answer:
I would say yes, this is a good time to begin your planning and planting of fall blooming bulbs. You are correct that fall blooming bulbs have a tendency to come up rather quickly, whether they are Colchicum, Crocus, or Cyclamen. The ideal is to plant roughly a month before the expected bloom time. Therefore late July or August is the appropriate time to plant. Some companies and seasoned individuals recommend getting started earlier, and the reason for that is to ensure that you get the bulbs that you want before it is too late. Because the selection of applicable fall blooming bulbs for our area is not as great as that of spring blooming bulbs, growers recommend buying early to make sure that your order is placed, processed, and shipped in a timely fashion. If you end up ordering and getting your bulbs too late you may find that the bulbs have already started to push their blooms before they have had the chance of being planted and establishing new roots. This may lead to a poor first bloom in your garden. To have the best chance of a decent bloom, plant your fall blooming bulbs in early August in well-drained soil and water during periods of drought.

Also, while we are on the topic, remember that most fall blooming bulbs put up their foliage in the spring, completely separately from the flower. The spring foliage is the bulbs chance to photosynthesize and store energy and carbohydrates for the upcoming fall flower. Many people forget where they planted their fall blooming bulbs and when the foliage comes up in spring they cut it back thinking it is some sort of weed. Then when the flowers emerge in fall, with diminished energy reserves, and the flower is less than spectacular people wonder why that is.

Therefore, order your fall blooming bulbs now and get them planted before the middle of August. Water them in times of drought and make sure they are in well-drained soil so that you do not run the risk of rotting the bulbs themselves. Lastly, if you fear you may not remember where they are planted, consider marking or mapping them so that you do not accidentally remove the foliage in spring. Enjoy!

Powdery Mildew on My Campsis grandiflora

Question:
My mature Campsis grandiflora is showing signs of a whitish/grayish film on some of its leaves. This has happened in the past, but never much before late September or October. Is this powdery mildew, or perhaps something else, and what might you suggest to eradicate it?

Answer:
Your situation does sound like a case of powdery mildew. Since it has been rather warm already this summer and with the few extremely heavy rainstorms we have gotten, it does not seem all that peculiar that the issue is affecting your Campsis earlier than usual. Campsis grandiflora is prone to powdery mildew but luckily these days there are cultivars being bred and sold that are considered to be more resistant. As you probably know from past years experience this fungal issue is not going to kill your Campsis, but the white film on the leaves is unsightly and does not help the plant as it tries to photosynthesize. The best solution that I have learned over the years is a homemade concoction that you use as a foliar spray. Add to a gallon of water two tablespoons baking soda and a drop of dish soap (Palmolive, Dawn, etc.) to give the mix a little viscosity. Once this is mixed, use it as a foliar spray and cover as much of your vine as possible. Continue to apply until the mildew seems to diminish. It may take a few applications over two or three weeks’ time. This usually does the trick.

Otherwise, think about the amount of airflow in the area where the vine is. Powdery mildew often occurs because of a lack of decent airflow, therefore pruning either the vine or other trees and shrubs in the area might prevent this from becoming such an issue in the future. My last thought is that Campsis grandiflora can be rather drought tolerant once established. Since you describe the vine as being mature then I would think you can cut back on supplemental watering at this time of year and hopefully the plant will still grow and flower well for you without the added powdery mildew.

Hibiscus in Nassau County, New York

Question:
I know I saw beautiful hibiscus decorative bushes in Nassau county last year. They were a pretty color, perhaps coral. I have been told the only hibiscus bush that would grow in our climate is the hardy hibiscus. I have looked on line under that topic and have not found the tropical looking - but cold weather hibiscus I so desperately want. Can you help me?

Answer:
There are essentially three different kinds of hibiscus that we commonly find here in the New York. One is a tropical shrub, one is a perennial, and one is a woody shrub. For future reference, when searching for plants or plant information, try and familiarize yourself with the botanical name of the plant. Knowing the scientific genus and/or species of a plant makes it much easier to find credible information, whether it be in a book or on the internet.

Hibiscus rosa-sinensis is a tropical shrub that is commonly sold as an annual in our area. They may be sold in shrub form or pruned up on a standard, a single trunk, to look like a small tree. They do have that large hibiscus flower and there can be lots of color variation, from white to yellow to red and every color in between. They are popular because with enough sun and water they can continue to bloom all summer long. They are not winter hardy, however, so come fall they will die unless you choose to move them inside to over-winter them indoors.

Hibiscus moscheutos, commonly called swamp rose mallow, is the plant most people call “hardy hibiscus”. It is a native perennial plant and does come back every year. This plant puts up skinny five or six feet tall stems with very large hibiscus flowers on top. Because it is a perennial, the duration of bloom is less than that of the tropical species, and they usually flower in late July or August. These plants thrive in full sun and very wet conditions, such as a low wetland or bog. Hibiscus moscheutos has very large flowers that are usually red or pink, but again, growers are introducing more color variation into the trade.

Lastly, there is Hibiscus syriacus, or rose-of-sharon. This is a woody shrub that is hardy to our climate and loves full sun as well. It is a very aggressive growing shrub that puts up many branches with grey bark and smaller hibiscus shaped flowers (perhaps two to three inches in diameter). This shrub also blooms later in the summer, but in full sun they can flower quite prolifically. These shrubs grow quickly and can seed themselves pretty freely around your property.