Common orange day lily has now officially become a pest, but cultivars are fine

Backyard Q&A

In The Garden

March 21, 2004|By Dennis Bishop | Dennis Bishop,Special to the Sun

I have heard that day lilies are now on the invasive species list. Is this true? Should I discontinue planting day lilies?

Yes, the common day lily (Hemerocallis fulva) is now on the invasive species list, but I do not think you need to stop planting day lilies. The real problem plant is the species plant itself, Hemerocallis fulva. This is the common orange day lily that is often seen growing along roadsides and in fields. It spreads by seeds and by expanding tuberous roots that form large clumps. There are thousands of registered day lily cultivars, and it is my understanding that they are not invasive and do not pose a threat to natural areas.

The only day lily I recall seeing in natural areas is the one cited above. If you have the common orange day lilies in your landscape, I suggest that you remove them. You can replace them with one of the superior, noninvasive cultivars.

I live in a Baltimore condominium with limited outdoor space, but I would like to grow a few vegetables. Can you provide a few tips on growing vegetables in containers?

It is easy to grow vegetables in containers. Because most vegetables grow to be large plants, I would build or buy large containers. While there may be other alternatives, it is probably best to use a soil-less mix containing peat moss and perlite or sand. This type of mix retains water well, but also provides good drainage, which is essential. Place your containers in a bright, sunny location and plant them at the same time of year as you would plant vegetables in the garden.

After planting, they will need to be watered frequently. During the hottest months of summer, you may need to water every day. You can fertilize with a liquid chemical fertilizer, a slow-release chemical fertilizer or with an organic fertilizer, such as fish emulsion. If you use chemical fertilizers, be careful not to overfertilize. Also, I would stick to small to medium-size plants. It would be difficult to grow a large plant like zucchini on a patio.

Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension Services. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site


1. Start tomato, eggplant and flower transplants this week. They can be started indoors under cool white fluorescent bulbs Keep bulbs 1-2 inches from plant tops and don't overwater.

2. Clean leaves and debris from ponds and resume feeding your fish when water temperatures stay in the 50s.

3. Shred leaves stockpiled over the winter before adding them to your compost bins.

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