Fact Sheets And Publications

Browse available resources.
Watch past Extension courses online!
Chat with a DE Master Gardener.
You have questions. We have answers!
Contact UD Extension staff.

Provisional Seashore Mallow Planting, Growing, and Harvesting Protocol

1. Seed bed preparation.

Background - We’ve prepared the seed bed both by tilling and by no-till using herbicides (glyphosate and gramoxone) to kill the weeds. Where we have nonsaline soil, weeds are a problem since we do not have herbicide-ready seashore mallow. Since mallow is a perennial, buildup of a seed-bank of weeds can be a problem. Morning glory, marestail, poke weed, dandelion, Virginia creeper, and some grasses (foxtail, fall panicum) are some of the offending plants. If the time between spraying and seeding is short, glyphosate is not a good choice since the seedlings are sensitive to that herbicide. If perennial weeds are part of the mix then tilling is probably the best option because the gramoxone probably won’t be effective on older perennial weeds.

Current needs - Five acres ready to plant seashore mallow. Given the time and not knowing the field conditions tilling would seem to be the best option, but local knowledge of the setting could alter the decision.

2. Planting.

Background - To date we have used a row planter with 19 inch rows with seeds ~3-5 inches apart and about 1 inch deep. Sorghum plates are the right size for the mallow seeds. We haven’t tried drilling the seeds, but that approach could be used. In small plots we have used 12 inch rows and that worked fine with the DE 22 line of mallow. We have planted in mid-May to Mid-June.

Current needs - Five acres planted soon. Method dependent on discussion.

3. Pre-emergent herbicides.

Background - In the initial planting year we have used pre-emergent herbicides. Dual Max 1 pt per acre plus 0.25% surfactant in 25 gals of water/ acre. In subsequent years, a quart of Atrazine and 0.5 oz of Sandea is added to the mixture. A quart of gyphosate per acre can be applied to kill winter and early spring perennial and annual weeds. The Atrizine use was determined safe in trials by Mark VanGessel and that for Sandea and glyphosate by Tony Freeman in field tests.

Current needs - At the time of planting apply the Dual herbicide. In the second year before emergence spray with the Dual, Atrizine, and Sandea.
4. Fertilizer.

Background - Fertilizer application is generally made based on soil testing. Response trials are underway in New Jersey at the USDA Cape May Plant Materials Center. As a relative of cotton and okra we believe Seashore mallow has a high feeding rate on potash and is sensitive to nitrogen. High nitrogen will favor stem growth over fruit development. For the current project we are
especially interested in the very absorbent stem fibers for bedding for poultry, consequently high nitrogen is desirable. Of the micronutrients boron is especially important to prevent abortion of seed pods. The optimum pH is probably between 6.2 and 6.5. At the Freeman farm this year we applied 85 N 34 P 104K per acre.

Current needs – Depends on field conditions. We want to push vegetative growth this first year because the goal is to maximize stem production for poultry bedding.

5. Irrigation.

Background - Some years we have irrigated at the Freeman farm and some year’s we have not. Irrigation, when it was done, was once or twice during the season. Obviously, a newly planted crop is more vulnerable to drought than an established one and those in the second year and older are most resistant. Some of the physiological characteristics that confer salt tolerance to seashore mallow also enhance drought tolerance. In areas where soils or irrigation water are salty the ability of the plants to tolerate salt makes those soils and water resources, rather than liabilities.

Current needs – Depends on water availability and weather conditions. The potential for irrigation, if necessary, is very desirable, but we would like to minimize its use.

6. Insect Pests.

Background - Occasionally we have found in older stands a build-up of flea-beetles and scentless plant bugs. We have found some flea-beetle resistance in several accessions, but none for the plant bugs as yet. Once we had Corman spray the Freeman’s field from the air with Warrior and Lannate. We have sprayed from the ground several times in our plots in Lewes for insects.

Current needs – Depends on conditions.

7. Post emergent herbicides.

Background - Southern States came down from Milford with a large sprayer to apply Poast as a grass herbicide.

Current needs – Depends on needs. With a good elimination of current weeds and pre-emergent application, weeds shouldn’t be a problem at least this first year.

8. Cutting and combining.

Background - We have cut the plants with a Ford version of a Haybine in early September. The time is chosen to be when the oldest seed pods are just beginning to shatter and the youngest are still not mature. We try to time the harvest to give us the maximum yield of mature good seeds. After the plants dry they are combined with a machine with a pickup head. We have direct combined on occasion, but we feel that the rough handling of the stems by that method results in more seed loss. We have been looking for a swather to purchase to use in place of the cutter conditioner that would be available for any grower to use. We believe its use would reduce shattering loss even more.

Current needs – This first year with our focus on stems for poultry bedding we may want to pass on seed harvesting and let the seeds shatter. Many will germinate in the spring and thicken the stand in the summer of 2015. If we don’t harvest the seeds, the harvest of the stems can be delayed somewhat in the fall of 2014. We would want to harvest seeds from the 2015 crop.

9. Baling.

Background – After combining, the straw is then windrowed and baled.

Current needs - Cut, windrow, dry, and bale.

10. Winter cover crop.

Background - We have planted a winter cover crop many of the years to reduce nutrient loss and give freeze protection to the crowns of seashore mallow. Wheat or rye was better than barley, which proved hard to kill in the spring burn-down.

Current needs – Plant wheat or rye as a cover crop. These are brief backgrounds on what has been done in the past and ideas of what we need done this year. We will provide the seashore mallow seeds and provide $1000.00 per acre for five acres to be planted, tended, and harvested. We will get the baled straw to use in a comparison study of seashore mallow with traditional pine chip bedding. The grower will provide the fertilizer and herbicide chemicals. We do not expect to need to have the area sprayed for insects, if so we can either pay the grower to do it or he can contract it to be done by air at our expense. The second year of the crop will have somewhat different needs, namely it won’t need to be planted, but the seed will need to be harvested.


John L. Gallagher & Denise M. Seliskar – University of Delaware, Halophyte Biotechnology Center, 700 Pilottown Rd., Lewes, DE 19958 (jackg@udel.edu; seliskar@udel.edu; 302-645-4264; 302-645-4366)

UD Cooperative Extension

This institution is an equal opportunity provider.

In accordance with Federal law and U.S. Department of Agriculture policy, Cooperative Extension is prohibited from discriminating on the basis of race, color, national origin, sex, age, or disability.