Black bamboo flowering

Our stand of black bamboo that has flowered is dying back. It was already escaping its barrier, but now I am concerned about the flowers producing seed that take hold everywhere. When we cut it down, should we be careful about not letting seeds scatter? I’ve heard that when one bamboo flowers, it coincides with other bamboos flowering. Is there going to be a massive die-off of bamboo?

You can certainly lay out a tarp for your cut bamboo, its flowers, and any potential seeds. If you are curious about seed viability, you can put some in containers and wait to see if they germinate. Some bamboo species have larger seeds that are easier to see, while others are small and easily obscured by decaying flower parts. Seeds collected before they are mature are unlikely to germinate. Based on all of these details, I don’t think your Phyllostachys nigra will be sowing itself all over the garden or the compost pile.

According to The Gardener’s Guide to Growing Temperate Bamboos (Michael Bell, Timber Press, 2000), flowering may be partial or complete. With partial flowering (which sometimes precedes full flowering), some culms will keep on going and not die. “When a bamboo flowers completely, most of the leaves are replaced by flowers, transpiration is largely interrupted, and this triggers natural responses that hasten the aging of the culm,” eventually resulting in death.

Depending on the species of bamboo, flowering is a fairly infrequent occurrence, and there are multiple theories about what prompts it. It can happen once every 30-60 years up to intervals of over 120 years. (There are just a few unusual species that flower yearly.) Bell says anecdotal accounts suggest that bamboos rarely if ever set seeds but, in his experience, “it is very rare that bamboos flowering in earnest do not set some seed during one of the years of their flowering cycle.” Clumping (sympodial) bamboo species will flower in winter and produce seed in spring, while running (monopodial) species like your black bamboo will flower in summer and produce seed in fall.

You mention the phenomenon of many bamboos flowering in unison. This is sometimes called mass synchronous flowering, or gregarious flowering, and can occur across the globe. According to Bamboo by Robert Austin and Koichiro Ueda (Weatherhill, 1970), “practically every bamboo of the same species, young or old and however widely separated they may be […] will flower in or about the same year.” Flowering in bamboo is complex and incompletely understood. A more recent scientific article, “The Bamboo Flowering Cycle Sheds Light on Flowering Diversity” by Xiao Zheng et al., classifies flowering into four categories: sporadic, massive synchronized, combined massive synchronized and sporadic, and partial flowering. Depending on the species of bamboo, regeneration can occur through sexual reproduction (seeds) or asexual reproduction (rhizomes forming small, weak shoots at first, as “the proportion of flowering bamboo generally first rises and then falls, while the proportion of non-flowering bamboo falls and then rises.” If your black bamboo dies, it is still possible you may observe some regeneration that follows this pattern.

Bamboo, Flowering of plants, Phyllostachys

Staghorn sumac flowers and fruit

I planted three staghorn sumacs several years ago. They have done well, and have nice fall color, but I was hoping to see the flowers and fruit. This summer, for the first time, there are flowers on one shrub. What prompted the change? Will the flowering plant have fruit?

Anecdotally, there are reports of Rhus typhina (staghorn or velvet sumac) taking a while to flower and fruit. If you don’t have flowers on more than one of your three plants, you are not likely to get fruit (unless your flowering plant is female and someone nearby has a male, in case your other two are also female). Rhus typhina and Rhus glabra (smooth sumac) are dioecious, meaning that they produce male and female flowers (yellow green upright cone-shaped panicles) on separate plants. Plants of both sexes need to be grown together, and pollen from the male flowers needs to reach the female flowers, for the the upright clusters of the fuzzy disc-shaped dark red fruit (berry-like drupes) to develop on the female plants. These fruit clusters are colloquially referred to as ‘bobs.’

You can examine the flowers on your plant closely (with a hand lens) to determine if they are male or female. Male flowers tend to be larger and have five yellow-tipped stamens, while female flowers have a three-lobed style in the center, and a calyx with five pointed lobes nearly the same length as the petals. Both flower stalks and calyx are densely hairy. [Source: Minnesota Wild Flowers field guide online] Here are additional photos to clarify the description.

Failure to flower, Failure to fruit, Flowering of plants, Rhus

Lilac blooming habits

I have a lilac shrub that is about six or seven years old and blooms every other year. This seems very odd to me. Most lilacs bloom every year. Is blooming every other year normal? It is planted in optimal conditions and looks very healthy.

Quoted directly from Lilacs for the Garden, by J. Bennett (2002, p. 99): “Some lilacs, especially cultivars of the common lilac (Syringa vulgaris) bloom better, or only, in alternate years. Pruning the plant soon after it does bloom may encourage flowers the next year.”
University of Nebraska Extension says that “removing the seed capsules soon after flowering has been reported to alter the every-other-year flowering cycle in some lilacs. This is because less energy goes into the current year’s seed production and more into the next year’s flower production. Some researchers agree with this recommendation and some do not. Removing seed capsules also improves the plant’s appearance.”

I could not find a list of which cultivars do this. You might consult the International Lilac Society to see if a list exists.

Another resource is the Hulda Klager Lilac Gardens (in Woodland, WA about 30 minutes north of Portland).

Flowering of plants, Syringa

propagating Brugmansia from seed

Can you give me specific directions on how to germinate Brugmansia seed and care for the seedlings. Also, at what age or size do these plants flower?

The following information is quoted from the book Brugmansia and Datura: Angel’s Trumpets and Thorn Apples (by Ulrike and Hans-Geog Preissel, 2002, p. 74):

The fresh seed should be sown as early as possible, at temperatures between 64–79 F. Cover the seed with approximately 1/5 (.20) inch of humus, which must be kept wet.

The seed is relatively large and is pressed lightly into the humus to ensure contact with the moist planting mix. Initially cover the seed box with a glass plate to provide optimal humidity. At temperatures around 68 F, the various species of Brugmansia germinate very differently. As a rule, germination takes between 10 and 20 days. The young seedlings can then be planted out directly into small containers.</p?

Young plants that are grown from seed go through an immature phase, easily recognized by the change in leaf shape. The plants do not reach flowering maturity until the end of this immature phase. The length of time before the first flowering varies with the species. On average, most Brugmansia flower for the first time when the plant is between 2.5–5 feet in size. If they are well cultivated, then they will usually
reach this size in six to nine months.

Plants grown from seed can look very different. They differ not only in leaf shape and size, flower shape, color and size, but also in other traits, such as susceptibility to diseases or willingness to flower. The possibilities are almost endless and many interesting and valuable discoveries are undoubtedly waiting to be made…

crocus and daffodils failure to flower

Many of my crocus and daffodils (especially crocus) didn’t flower this year. They don’t seem to be in need of separating – none of them have been in the ground for over 3 years and I don’t think I overfertilized. Otherwise they seem quite healthy. What might be the problem?

The most common reasons that hardy bulbs like crocus and daffodils fail to flower are these:

1. Planting location: they need to be planted in full sun.
Bulbs; a complete handbook of bulbs, corms, and tubers (by R. Genders, 1973)

2. Drainage or heat: spring flowering bulbs planted in poorly drained soil or too near a heated basement (where heat from the structure warms the soil and interferes with the bulbs’ necessary cold treatment) will rot or simply fail to flower.
Daffodils for Home, Garden and Show (by D. Barnes, 1987)

3. Fertilization: high nitrogen fertilizers encourage lush green growth and discourage flowering.
Daffodils for American Gardens (by B. Heath, 1995)

When trees fail to flower

Chionanthus virginicus–at what time can this tree be expected to bloom? And how does it do in the Pacific Northwest? Does this tree needs to reach a certain age or maturity before it blooms–similar to Cornus kousa or some magnolias? Or could it be a cultural problem that keeps it from blooming? Mine is in full sun, moist/fertile soil. It’s been there 3 years and is probably 6 feet tall and over 5 years old (purchased balled and burlapped). Could it be getting too much nitrogen, as it is on the edge of the lawn?

According to local author Arthur Lee Jacobson’s book, North American Landscape Trees (Ten Speed Press, 1996), Chionanthus virginicus blooms between May and July, depending on the year and the latitude. Male and female flowers are on separate trees, and male flowers are more showy. Sunset Western Garden Book also says that this tree flowers here in late spring to early summer. Here is what Oregon State University’s web site of Landscape Plants says:

“Deciduous, large shrub or small tree, spreading, open, 12-20 ft (4-6 m) tall with an equal spread, larger in the wild. Leaves simple, opposite, sub-opposite, narrow-elliptic to oblong or obovate-oblong, 7.5-20 cm long, acute to acuminate, margin entire, glossy dark green above, underside paler and pubescent, at least on veins. Dioecious – male and female plants, but some have perfect flowers. White flowers showy, in fleecy, soft clusters in late spring. Fruit about 13 mm long, egg-shaped, dark blue in late summer.
Sun to partial shade. Adaptable but does best in moist, fertile, acid soils. Slow growing. Male trees reportedly have showier flowers.”

There are a number of reasons why your tree has not flowered. According to The Hillier Manual of Trees and Shrubs, flowers are not seen on young trees (no specifics as to age of maturity, unfortunately). University of Maryland Extension indicates other reasons plants fail to flower.

The full sun and moist soil sound like ideal conditions. It is quite possible that nitrogen-heavy fertilizer could contribute to the lack of flowers. You might consider applying compost to your lawn for nutrients instead of whatever you may have been using. Perhaps you could avoid using the fertilizer and give the tree at least another year to adjust and attempt to flower.

on ever-blooming lilacs

Is there such a thing as a repeat-blooming lilac?

There is a relatively new (2009) lilac cultivar named ‘Bloomerang’ which is a repeat bloomer, described in this amusing article in Macleans.ca by Anne Kingston, entitled “Ever-blooming lilac wars.” The article also mentions ‘Miss Kim’ and ‘Josee’ as repeat bloomers. Reblooming lilacs seem to appeal to some but to be an offense to others, who want lilac blooms to remain seasonal signifiers:
“The reason people love lilacs, of course, is because of their temporal timetable. Their first (and only) flowering is greeted with joy, tinged by the knowledge it will be fleeting, poetically so; no one has ever complained of being bored by lilacs. Tamper with that and you hit a primal nerve, as the Bloomerang clearly has.”