Tall Plants for Privacy, Midsummer Planting and Care

Tall flowers do not just need taller pots or more water to give privacy; they need the right varieties, spacing, soil depth, and support, and you can get a useful screen this season if you follow the steps below. In July you can plant or add transplants of tall plants and see a 3 to 8 foot screen by late summer, depending on the choices below.

Quick answer, can tall plants give a usable privacy screen this summer

One sentence summary, realistic expectations for July plantings

Yes, you can get a useful privacy screen this season if you pick fast-growing annuals or vigorous vines, space them correctly, give 12 to 18 inches of good soil, and stake or trellis before the plants get floppy.

People searching now want an immediate yes or no and how fast screening appears. Annual sunflowers, sorghum-sudangrass, giant millet, cannas, and trellised vines will show rapid height gain in 4 to 8 weeks from planting or transplant. Perennials and ornamental grasses take longer and are better for next year.

What you need to plant tall privacy flowers this weekend

Materials and exact quantities, for a 10 foot by 2 foot linear bed

• Bed area: 10 feet long by 2 feet wide, surface area 20 square feet. For 12 inches of soil you need 20 cubic feet of finished mix, about 0.75 cubic yards.
• Topsoil and compost: Mix 14 cubic feet screened topsoil plus 6 cubic feet compost, or buy 27 standard 0.75 cubic foot bags of blended topsoil/compost to make ~20 cubic feet. Aim for a 2 to 1 topsoil to compost ratio by volume.
• Plants, number and spacing for common choices:
• Sunflowers, transplants 8 to 12 inch size: plant 6 to 8 plants spaced 18 to 24 inches apart. Varieties: Helianthus annuus ‘Mammoth’ or ‘Russian Giant’.
• Canna lilies, 8 to 10 inch rhizome transplants: 6 plants spaced 18 inches apart. Varieties: ‘Tropicanna’ or ‘Bengal Tiger’.
• Sorghum-sudangrass (for a grassy screen), direct seed: sow 10 to 12 seeds per linear foot in a 2 inch deep drill; thin to 6 to 8 stalks per foot, final spacing roughly 6 to 8 inches.
• Ornamental millet, direct seed or transplants: plant 8 plants spaced 12 inches apart. Variety: Pennisetum glaucum ‘Purple Majesty’.
• Trellised vines on a 6 foot tall support, transplants or seedlings: plant 10 to 12 vines 12 inches apart. Good choices: scarlet runner bean, hyacinth bean, or morning glory for quick cover.
• Quick mixed screen using transplants and vines: 6 sunflowers spaced 18 inches plus 10 vine plugs along a 6 foot trellis behind them.
• Soil depth: Give at least 12 inches of loose, amended soil for most transplants. For very large roots like cannas or tall grasses give 18 inches.
• Fertilizer and amendments: Mix 1 cup slow-release balanced fertilizer (10-10-10) into the top 3 inches of bed (for the 20 sq ft bed). Add an extra 2 gallons of compost spread evenly and worked in.
• Mulch: 2 inches of shredded bark or straw, roughly 0.6 cubic feet, to conserve moisture. Keep mulch 2 inches away from stems.
• Stakes and supports: For plants expected over 6 feet use 8 foot bamboo stakes, one per plant, or a 6 foot chain link or wood trellis spanning the bed. For sunflowers 6 foot stakes are fine for 6 to 8 foot varieties; for 10 to 12 foot plants use 8 foot stakes plus an additional support line.
• Ties: 10 soft cloth or Velcro plant ties. Use two ties per stake at 12 and 24 inches above soil to start.
• Watering: Hose with adjustable flow or soaker hose long enough to cover 10 feet. For the bed you will deliver 1 to 1.5 inches of water per week total, applied as two deep soaks during hot July weeks. That equals 12.5 to 18.5 gallons per week for the whole bed.

Step by step, how to plant and get a screen fast

1. Check frost and soil temperature.

   In central Ohio zone 6b the last spring frost is roughly May 10 to May 20, and the first fall frost is roughly October 15 to October 25. In midsummer you are safe to plant warm season annuals. Make adjustments by zone: warmer zones plant earlier, colder zones wait until after last frost. For transplants, soil should be above 60 degrees Fahrenheit for good root growth.

2. Prepare the bed to 12 to 18 inches depth.

   Remove grass and weeds, loosen soil to 12 inches with a fork. For heavy clay loosen to 18 inches and add 2 inches of compost. Level and water once to settle the soil.

3. Mix soil and fertilizer.

   For a 10 by 2 foot bed, work in 6 cubic feet of compost with 14 cubic feet of topsoil, or roughly 27 bags of blended topsoil. Broadcast 1 cup slow-release 10-10-10 into the top 3 inches and rake smooth.

4. Layout plant spacing before you set plants.

   Mark positions with a stick. For transplants 18 to 24 inches apart gives enough leaf cover and air flow. If using a trellis, set the trellis at the back edge of the bed and plant vines 12 inches apart at the base.

5. Plant transplants and seeds correctly.

   Dig holes the same depth as the root ball. Set transplant so crown sits at soil level. Backfill and firm gently. Water each plant with one gallon immediately. For direct seeding like sorghum or millet, plant seeds 1 to 2 inches deep, keep moist until germination.

6. Stake or install support immediately.

   Drive stakes 6 to 8 inches past the bottom of the root ball into the soil, so stakes are stable. Tie plants loosely at two heights. Install trellis hardware before vines reach the support to avoid root disturbance.

7. Mulch and finish.

   Spread 2 inches of mulch around plants but keep the mulch 2 inches away from stems. Mulch will cut watering needs and slow weeds. Water the whole bed to settle mulch.

Watering through midsummer heat with exact numbers

In July you want deep, infrequent soaks rather than light daily misting. Aim for 1 to 1.5 inches of water per week for this 20 square foot bed. That equals 12.5 to 18.5 gallons per week. Split that into two waterings: twice each week, 6.25 to 9.25 gallons per soaking.

Per-plant guidance: if you have eight plants, that is about 1.5 to 2.5 gallons per plant per week, applied as 0.75 to 1.25 gallons twice a week. Measure a gallon jug to check your hose output, or place a tuna can and time how long the hose takes to fill it to deliver known amounts.

Water early in the morning before 9 a.m. If it is 95 degrees or hotter and plants show wilting midday, add a third, light soak late afternoon, then protect crowns with temporary 30 percent shade cloth during heat waves for 3 to 5 days.

For timing and methods that match vegetable beds, see when to water vegetable plants in summer at the Babble On Gardens.

Feeding and staking schedule, midsummer through first frost

• Side-dress with 1 tablespoon granular 10-10-10 per plant every four weeks for heavy feeders like sunflowers and cannas. Alternatively, use a water-soluble 20-20-20 at 1 tablespoon per gallon every two weeks for visible growth boost.
• Check ties every two weeks and raise ties as plants grow. Add a second stake or cross brace if head weight pulls plants sideways.
• If seed heads form and you need leaf cover for privacy, pinch the top of a few plants to delay big seed heads and keep leafy mass.

Common failure modes and how to avoid them

• Planting too shallow or in thin soil. I lost a whole row to wind when roots were in compacted subsoil. Solution: loosen soil 12 to 18 inches and add compost before planting.
• Skipping support until plants are tall. I watched sunflowers flop and suffer root damage after staking late. Drive stakes at planting time so you do not disturb roots later.
• Crowding plants. Too tight spacing reduces airflow and encourages mildew and rot. Stick to 12 to 24 inch spacing listed above and remove lower leaves if air is stagnant.
• Watering only at the surface. Shallow wetting makes weak roots and blowovers. Use deep soaks delivering measured gallons per plant.

Comparison table of fast screening options

If you want the extra context on raised beds before you start, see raised bed gardening for beginners for soil mixes and bed construction tips. For staking tips that also help tomato plants, you can check how to grow tomatoes in containers for tying methods that work here. If you are new and worried about small mistakes, the common mistakes new gardeners make article will save time.