Ask the Experts

NANDINA TOXIC FOR BIRDS

Question: I have grown Nandina for years in my landscape. I love them for the red fall color and the bright red berries. As I was walking through the garden with a friend, she told me to get rid of the Nandina as it kills birds. Is that true, should I remove the plant?

Answer: Your friend is correct. Nandina, Nandina domestica or Heavenly Bamboo, is prized for its bright red berry clusters. According to the Audubon Society, various sources have confirmed that the berries contain cyanide and other alkaloids. These compounds are toxic to birds and other mammals. Cedar Waxwings, Robins and Bluebirds can die from eating the berries.

Bird lovers are calling for the removal of this plant from the landscape due to the berries. Nandina has also been found to be invasive in some regions, although it does not appear to be invasive in the Kansas City area.

You have several options. One, remove the plant. Two, remove the berries before they mature and are consumed by birds. Or, three, plant dwarf varieties such as ‘Fire Power,’ ‘Gulf Stream,’ or ‘Sunray.’ Dwarf varieties rarely produce flowers and berries but still display the beautiful fall color.

EAT YOUR PEAS

Question: I love edible pea pods. They are tasty, eaten raw or steamed. The problem is our heat tends to end the crop early. Are there any tricks to extending the season? What about a fall planting?

Answer: Edible pod peas, also known as snow peas or sugar peas, are consumed when young and tender, eating the pod and all. All peas thrive in cool weather and our short springs can bring the harvest to an end early. Peas are one of the few crops that germinate and start in very cool soils, 40 degrees. One trick to try is planting in late FebruNandina leaves and berries are toxic and may be harmful to birds, humans, grazing animals and cats.

ary or early March. Prepare the soil now so the seeds can be poked into the ground, germinate and start to grow. This early planting may help give you a jump on the season.

A fall crop is challenging as they germinate and establish poorly under the late July or August heat. If we have a milder summer, a fall crop might work. I would not expect good yields under the summer heat and higher soil temperatures.

KNOTWEED, GET OUTTA HERE

Question: Last year, you identified a weed problem in my yard. I believe you called it knotweed. Remind me again how to get rid of knotweed.

Answer: Knotweed must be the best name ever. I have identified this broadleaf weed before, and the response is, “yes, it is a weed.” Get it – “knot” weed.

Knotweed is interesting as it is usually found in heavily compacted soils. The best defense may be tillage or aeration to reduce compaction. This annual germinates in late February to early March and gets a hold before traditional crabgrass control products are applied. Ice plant ‘Fire Spinner’ is one variety that tends to be more tolerant of wet clay soil.

Besides reducing compaction, here are other options.

Crabgrass control products are labeled for knotweed, but it must be applied prior to germination. Apply in the late fall for best control. Your other option is to spot treat with a broadleaf herbicide after germination in the very late winter or early spring. It does die out once the temperatures heat up in the summer.

HARDY ICE PLANT, NOT SO MUCH

Question: I have tried to grow hardy ice plant, and even though it is listed as hardy to zone 4 to 6, it just doesn’t survive. What am I doing wrong?

Answer: Hardy ice plant, or Delosperma, is grown for its brightly colored flowers with its succulent looking foliage. Here is the issue with ice plant. It takes our winter cold but does not tolerate cold, wet, clay soils. Ice plant tends to be an annual or short-term perennial succumbing to root rot in our area without proper siting.

Ice plant grows best in extremely well- and fast-draining soils, tending to have a more gravely, sandy texture and less clay. It does best in dry winters. Cold, wet winter soils spell doom. Think rock garden conditions when planting ice plant. Many people enjoy it as an annual as it does tend to flower during the summer. The variety ‘Fire Spinner’ tends to be one of the more tolerant of our wet clay soils.

It lasts maybe a season or two in our demonstration gardens but have given up and planted more durable perennials instead.

ORNAMENTAL SWEET POTATO VINE PRODUCED

Question: Imagine my surprise when I removed frost-killed sweet potato vines from my containers and buried deep in the pots were sweet potatoes the size of a small football. Two questions – Are they edible, can I eat them? And can I start new plants next year by saving the tubers?

Answer: Ornamental sweet potatoes produce tubers just like those varieties grown in the vegetable garden. The difference is that the ornamentals are grown for foliage, not for food. Generally, ornamental sweet potatoes are mealy, dry and do not have any flavor. If you want to try and eat it, go ahead. But most people report there is not enough butter or cheese in the world to make them tasty.

As for saving to start new plants, it is possible. Store the tubers in a cool, dry location for the winter. Then you can sprout them in the spring. Remember the kid’s project of the sweet potato supported in a glass of water with toothpicks? This method works. Be sure to place the tuber right side up, leaving it a few inches out of the water. After some time in the water, sprouts will develop. Once these shoots reach about 4 to 6 inches, break them off the tuber. They are ready for planting into a small container with potting soil to grow roots. After a couple weeks, they will be rooted and ready to plant.

DENNIS PATTON Horticulture Agent

Dennis Patton is the horticulture agent for Johnson County K-State Research and Extension. For free information fact sheets, visit www.johnson.ksu.edu, or call the Extension office at 913-715-7000.