Gardening Q&A

Gardening by the Yard : Episode GBY-802 -- More Projects »
PHOTO

Figure A
PHOTO

Figure B
PHOTO

Figure C
Q: I want to plant some heavenly bamboo, but I'm afraid of it spreading. Any suggestions?

A: Yeah, plant away! You see heavenly bamboo isn't a bamboo at all, and it doesn't spread. It's another name for nandina, an evergreen shrub that is hardy to Zone 6 and is extremely popular in southern gardens (figure A). It also makes a great container plant in northern gardens. Improved varieties, including dwarfs like this 'Moon Bay' (figure B), are beautiful, carefree and produce great fall foliage (figure C).

Q: Is Cornus kousa a tree or a shrub?

PHOTO

Figure D

PHOTO

Figure E

A: Cornus kousa, the Chinese dogwood, can be trained either as a single trunk tree or multi-trunk shrub (figure D), although these are typically harder to find at a nursery. Either way, however, you'll be proud to own one because they are among the most beautiful small, shade tolerant trees, and they bloom about a month later than the native Cornus florida. They also produce gorgeous fall foliage (figure E).

Q: Are there any pine trees that grow well in shade?

PHOTO

Figure F
PHOTO

Figure G
A: Well, unfortunately, most pine trees require a good bit of sun, at least six hours a day. But as luck would have it, there's one pine tree that actually requires a good bit of shade, especially in the south. It's Pinus flexilis, also known as the limber pine (figure F). A slow grower that's hardy to Zone 2, the limber pine is so named because its branches are extremely flexible. It's a nice choice for small spaces. 'Vanderwolf's Pyramid' has blue-green needles (figure G) that blend beautifully with many landscape plants.

Q: What are the absolute minimum temperatures for tropical plants?

A: That's a very good question because there are no published reports on just how low the temperature can go before a tropical plant succumbs to tissue damage. By definition, a tropical plant is native to the tropics and in the U.S., that means Zone 11, which includes the southern tip of Florida, a narrow strip along the Gulf Coast of Texas and all but the mountainous regions of Hawaii.

However, outside of Zone 11, tropical plants are typically grown indoors as houseplants year round, or as container plants on the patio. And since the latter are usually brought indoors long before the first hard freeze, there's not a lot of definitive data on the absolute minimum temperatures. But interestingly, some tropical plants can survive pretty cool temperatures--several degrees below freezing.

For example, just last week, temperatures at my place bottomed out at 20 degrees, but my palms are doing fine. I admit I'm pushing my luck, so I'll bring them in soon. If you're concerned about a specific tropical plant, one that you want to successfully over winter indoors, then I'd suggest taking it inside before temperatures drop to about 40 to 45 degrees F.

Q: What's the difference between a Datura and a Brugmansia?

PHOTO

Figure H

A: This is difficult to answer because even botanists can't seem to agree on the difference between the two. But it's worth growing one, regardless of what the label says it is. These flowers, known as angel's trumpet (figure H), open at night and release a wonderfully musky aroma. It's been a little chilly here, so mine isn't looking all that great right now, but at least I know it can handle temperatures down to 28 degrees F. I also know I can overwinter it without any problem or protection in the garage. And one more thing, all parts of both plants are extremely poisonous, so keep them away from children and pets.

Q: What's your favorite plant for fall color?

PHOTO

Figure I
A: That's like asking me if I have a favorite kid! Let's face it, there are all kinds of plants that produce phenomenal fall foliage including two I mentioned earlier, nandina and dogwoods of all kinds. I also love fothergilla and viburnums, but if I had to zero in on one plant group, it would almost certainly be the Japanese maples (figure I). I think the colors they produce are the most intense, especially those that turn red in the fall. But then again, the yellows and orange-brown combos are great, too.