Q: I could use some filler plants to make my porch look more lush. I know there’s caladium and a handful of annual flowers (fuchsia, torenia, impatiens) that can be used, but is there anything that grows faster or fuller? It doesn’t need to bloom.
A: I like to use tropical plants (houseplants, mainly) as the highlight plant or a filler for summer containers in semi-shade to mostly shade. Bring them indoors around mid-autumn to overwinter, or just treat them like a disposable annual that gets replaced next year. For lots of direct sun, you might want to stick with traditional annuals or seek tropicals like palms, Chinese hibiscus, or climbers like mandevilla or passionflower. Overwintering the tropicals without much decline can be tricky, though some gardeners have success.
Most houseplants grown for their foliage don’t need or want too much direct sun, and their foliage alone can provide an interesting texture or color contrast with annuals. They often start out larger than typical annuals, since they tend to be older plants. Those not producing flowers can also afford to put more energy into additional leaf growth.
Two of my favored leafy accents are ferns and begonias. Begonias are a diverse group and many can have showy blooms, but I am drawn to those with decorative leaves, like the Rex cultivars. Their foliage can provide bullate (bumpy) texture or a bristly-looking coating of hairs, and leaf markings can be silver, purple-black, pink, red, or lime-green. Several begonias look opalescent if viewed from the right angle, their leaf structure giving a unique glitter-like effect best appreciated up close.
Within the fern group, one large-growing and easily sourced candidate is Boston fern. It works well as a lush hanging basket plant under a porch overhang or as a specimen in a tall urn, since the fronds get long and drape. Or, use it as a companion to other container tropicals or annuals, provided the pot is large enough.
The group of plants we know by this name today was actually one particular cultivar (‘Bostoniensis’) of a sword fern species (Nephrolepis exaltata) native to parts of Florida, Mexico, and south into upper South America. Wisconsin Extension notes that it was selected out of a fern shipment to Boston 130 years ago, and the name has stuck since.
Other cultivars exist for this species, including dwarf forms that are easier to fit into snug spaces or even to grow in a spacious terrarium inside. My favorites are a golden-leaved version, “Rita’s Gold,” which I’ve grown alongside a dark-leaved begonia, and “Suzi Wong,” which is so fine-leaved that it looks like a plant version of cotton candy (which happens to be an alternative common name).
Q: Can I trim my azalea bushes now? A: Probably, if they just finished blooming a few weeks ago (some azalea cultivars bloom earlier than others). Waiting any later, risks removal of next year’s flowers, though it won’t hurt the plant.
The reason for trimming will dictate a bit of the timing, though, since regular trimming is not otherwise necessary for azaleas. Is it getting too tall and blocking a window or sight line at the end of a driveway? If so, prune it whenever you need to (though ideally not in autumn) and just accept that some of next year’s flowers might be sacrificed. Otherwise, azaleas grow best with minimal pruning, and certainly no regular shearing.
If an azalea shrub is continually growing so well as to be too big for its location, consider moving it or periodically cutting it way back so it has several years to regrow before getting too big again. (This is called rejuvenation or renewal pruning, and may help to rehab the look of a tired, leggy plant whose inner branches are bare.) Ideally, though, grow a cultivar that will mature around the size a space can accommodate without relying on pruning, because that will be easier on both the plant and yourself.
Several azalea cultivars exist, and many are dwarf and stay quite compact on their own; or, they grow slowly enough that it may take them at least a decade to reach the typical height of a window ledge or mailbox. University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information atextension.umd.edu/hgic. Click “Ask Extension” to send questions and photos.
