Articles

Why Are My Tomato Leaves Curling?

Upward curling tomato leave indicates stress more often than disease.

“Lots of my tomato plants have curling upward leaves, and in most cases only edge damage. Why?” Questions from James of Greenville, South Carolina

Answer: There is a Tomato Yellow Leaf Curl Virus, but your plant lacks several of the symptoms, including stunting, yellowing, and eventual leaf browning. Tomato plants more commonly experience physiological leaf curl when subjected to various environmental stresses. In this case, I believe yours is caused by environmental stress.  Here are four possible sources of stress.

Environmental Tomato Leaf Curl Causes

  1. Too little or too much water — Vines fail to grow as well when water is lacking, and they develop root rot when there is too much water. Either can cause leaf curl. Regular, even watering will yield the best results.
  2. High heat — Temperatures over 85 degrees F will cause most tomato plants stress and sometimes leaf curl. Some tomatoes are more heat-tolerant. Two of the best heat-tolerant varieties include the large, red-fruited ‘Heatmaster‘, which can take the high heat of the South, and disease and heat-resistant ‘Heatwave II‘, which bears deep red tomatoes with good flavor.
  3. Wind stress — High winds cause rapid water loss from the leaves and stresses vines. Leaf curl can result.
  4. Herbicide damage – Glyphosate herbicide damage is most common. It can cause this type of leaf appearance if a small amount reached your tomatoes from a downwind application.

Could any possibilities be the cause? Please let me know. In the interim, click here to read more about leaf curl, and watch the video below about growing tomatoes to perfection!

Happy gardening!

Jessie Keith

Black Gold Horticulturist

Can I Grow Peonies Down South?

‘Coral Charm’ is a peony that grows better down South, and it is one of my favorites!

“I live in south Georgia and I would love to plant peonies, but I was told by a local nursery that they can’t survive here because we don’t have cold enough winters for them to reset, is this true?” Question from Ladonna of Naylor, Georgia

Answer: It is partially true. The most popular peonies in the US are common garden peonies (Paeonia lactiflora). The large, bushy plants produce loads of big, late-spring flowers and are hardy to USDA Hardiness Zones 3-7 (sometimes 3-8b), so you are on the edge of their hardiness. They do need winter cold for several months to produce blooms and survive in the long term, but Naylor, Georgia (USDA Hardiness Zones 8b) is cold enough to sustain some peonies. If you want to be on the safe side, there are other peonies that can survive with even less winter cold. This includes some tree peonies (Paeonia species and hybrids, varying zones, sometimes down to zone 9), and Intersectional (ITOH Hybrids (Zones 4-9), which are hybrids between common and tree peonies.

Peonies for Southern Gardeners

Here are seven good herbaceous peony varieties for southern gardens.

  1. ‘America’ (Zones 4-8b)- a single, red herbaceous peony that is award-winning and has HUGE blooms
  2. ‘Coral Charm‘ (Zones 3-8b) – a semi-double coral-pink award-winner (one of my favorites!)
  3. ‘Felix Crousse‘ (Zones 3-8b) – an herbaceous heirloom (1881) with fragrant double-red blooms
  4. ‘Festiva Maxima’ – an herbaceous heirloom (1881) with fragrant double-red blooms
  5. ‘Red Charm’ – an herbaceous peony with fragrant, deepest red, double blooms
  6. ‘Scarlet O’Hara’ (Zones 4-9) – Another exceptional single-red peony
  7. ‘Shirley Temple’ (Zones 3-8b) – a beautiful double peony of palest cream-pink

Click here to read more about caring for peonies, and click here for a full list of peony nurseries approved by The American Peony Society! 

Happy gardening,

Jessie Keith

Black Gold Horticulturist

What are Shade- and Sun-Loving Groundcovers for Florida?

Texas Frogfruit is a native groundcover that feeds bees and butterflies.

“Can you tell me, please, which ground cover plants do well in SW Florida, in a shady and wet location, as well as an area that is drier and gets sunshine most of the day!” Question from Colleen of Englewood, Florida

Answer: There are several groundcovers, for wet and dry areas, that are suited to your Zone 9 landscape.

Florida Groundcovers for Moist Shade

  • Ogon Golden Variegated Sweet Flag (Acorus graminius ‘Ogon’): This evergreen, grassy perennial will tolerate soil moisture, shade, and brings sunny yellow color to shaded spots.
  • Evergold Sedge (Carex hachijoensis ‘Evergold‘, Zones 5-10): Evergold produces moppy clumps of grass-like blades of green striped with gold. The plants will tolerate both moisture and shade. 
  • Snow Drift Caladium (Caladium hybrids, Zones 9-11): All Caladiums are beautiful, but snowdrift is extra elegant and brightens shady spots. They will grow well in moist soils and shade.
  • Fizzy Mizzy Sweetspire (Itea virginica Fizzy Mizzy): These compact shrubs grow well in partial shade, boggy soils, and are natives that feed wildlife. White, fragrant, spring flowers feed bees and butterflies and the fall leaves turn shades of russet-red.

Florida Groundcovers for Dry Sunshine

Texas Frogfruit (Phyla nodiflora, Zones 8-11): This semi-evergreen groundcover reaches 3-6 inches and produces small pinkish-white flower clusters that feed bees and butterflies. The flowers may appear from late spring to fall. It is a Florida native that can tolerate sunshine and partial sun as well as moist and dry soils.

Asian Jasmine (Trachelospermum asiaticum ‘Minima), Zones 8-11: The evergreen Asian jasmine is compact, slow-growing, and it has deep-green, glossy leaves that are bright red when they first emerge. Throughout the growing season, it produces small, white flowers that are fragrant. Established plants tolerate drought and light frost.

I hope that this list gives you some ideas.

Happy gardening!

Jessie Keith

Black Gold Horticulturist

Is Early October Too Early to Plant Turnips From Seed in Zone 7?

Plant Turnips From Seed

“Is it too late to start turnips from seed in zone 7?” Question from Patricia of Warrenton, North Carolina

Answer: It depends on your weather and the turnip. On average, they take around 40-50 days to yield roots from seed. If your Novembers remain reliably mild, then plant them. Another option is to build a cold-frame for growing winter root vegetables and greens. (Click here for  Tips for Cold Frame Gardening)

Good Turnip Varieties

If you want to give them a try, here are four excellent varieties:

  1. Old-fashioned ‘Purple Top White Globe’ (50 days) is a classic turnip with white roots, purple tops, and good flavor. The young leaves are favored in the South for turnip greens.
  2. Red-rooted ‘Scarlet Ohno Revival’ (50 days) is pretty and delicious fresh or cooked.
  3. White-rooted ‘Tokyo Market’ (35 days) grows very fast and has a fruity, sweet flavor, making it good for fresh eating.
  4. The purple-skinned ‘Nagasaki Akari Kabu‘ (50 days) is very flavorful and colorful.

Make sure to work up the soil before planting them and amend it with Black Gold Garden Compost Blend. I generally cover the seeds with a light sprinkling of Black Gold Canadian Sphagnum Peat Moss to help them stay moist and sprout quickly.

Happy gardening!

Jessie

Can I Grow Hydrangeas in Central Florida?

“I live in Central Florida, zone 9b, can I grow hydrangeas in this zone? I used to have them in Maryland as they are my favorite flower. Not sure about the sandy soil here.” Question from Eileen of Longwood, Florida

Answer: Many hydrangeas require cold winters to survive, but there are some truly beautiful hydrangeas that will grow well way down South. These are bigleaf hydrangea (Hydrangea macrophylla) varieties. (Click on this link to view many excellent bigleaf hydrangeas from Proven Winners.) Keep in mind, you are right on the most southerly edge of their heat tolerance. They are able to survive in USDA Hardiness Zones 5-9, so you will want to give them extra good care at planting time and protect them from scorching heat.

To keep your hydrangeas protected from the high heat of the day, plant them in a partially shaded location on the north side of your home, and amend the soil heavily with organic matter. Black Gold Canadian Sphagnum Peat Moss and Black Gold Garden Compost Blend will really boost levels of water-holding organic matter. Follow up with a 2- to 3-inch layer of fine bark mulch or pine straw to reduce surface evaporation. If you experience any dry periods, be sure to irrigate your shrubs as needed. It also pays to feed them with a quality fertilizer formulated for flowering shrubs.

Happy hydrangea growing!

Jessie Keith

Black Gold Horticulturist

What Are the Best Strawberry Varieties for Texas Gardeners?

What are the best strawberry varieties for Texas?

What are the best strawberry varieties for Texas? I really would like to enjoy them year-round, and I have the ability to grow them in a raised bed that can easily be covered.” Question from Deb or Alvarado, Texas

Answer: Great timing! I just planted 25 strawberries in my own Delaware garden, so strawberries are on my mind. There are two types of strawberries, June-bearing types that produce once a year, and everbearing types that produce one big crop in late spring and then keep yielding additional berries through the season. It sounds like you want the latter. Additionally, some strawberries are better adapted to warmer zones like yours. Three everbearing recommendations for southern gardens like yours include ‘Tribute‘ (medium-fruited, disease-resistant), ‘San Andreas’ (extra-large fruited, heat-tolerant), and ‘Seascape‘ (medium-fruited, disease-resistant). There are many more, but these three are very good choices that are commonly available.

Growing Strawberries

Strawberries grow best in soil that is well-drained, moisture-retentive, light, and high in organic matter. A soil with a slightly acid pH, between 5.5 to 6.5, is ideal. Amending with Black Gold Garden Soil, Peat Moss, or Compost Blend will boost your raised bed soil for strawberry growing. For further growing information and planting guidelines, please watch the video below.

Enjoy your strawberries.

Jessie Keith

Black Gold Horticulturist

When Should I Prune My Knockout® Roses?

 

“I live in South Louisiana.  When should I prune my Knockout roses?” Question from Deborah of Saint Amant, Louisiana

Answer: Many growers advocate you that prune shrub roses in late winter or spring before they have leafed out, but some rosarians disagree (see our Black Gold video on pruning hybrid tea roses below.). Either way, I like to prune mine at this time because it’s easier to make cuts on bare branches, and there’s less trouble with pests and diseases. But, Knockouts are everblooming and fast-growing, so you can be pretty carefree about when you prune them, especially down South. (Click here to read more about rose pruning.) Just be sure you use sterile pruning shears or loppers. To keep shears clean and reduce the chance of potentially moving pests or diseases from plant to plant, I dip mine in a 10% bleach solution between roses.

Happy rose pruning!

Jessie Keith

Black GoldHhorticulturist

When Do You Plant Onions and Potatoes in Southeast Texas?

“For Northeast Texas, when is the right time to plant onions and potatoes? Question from Ronnell of Linden, Texas

Answer: Potatoes like it cool, so you want to get them in the ground in late winter–February is a good month. Some varieties are better than others for growing in your area. ‘Yukon Gold’ is a good yellow variety to try, ‘Atlantic’ is a good white, and ‘Norland’ is a good red-skinned type. To read more about how to grow potatoes in your neck of the woods, click on this great Texas A&M article about growing potatoes in Texas.

Spring onions and leeks can be planted in February or March, but most traditional onions are best planted from October to December in Northeast Texas. (You might be able to get away with planting them now, if you’re fast!) Once again, there are some varieties that perform better in the South than others. To get all the details, click here for a great Texas A&M article about growing onions in Texas.

Happy gardening!

Jessie Keith

Black Gold Horticulturist

What Herbs Can I Grow in Central Florida?

What are the best herbs for Central Florida? Question from Sherry of Silver Springs, Florida.

Answer: You can grow common, heat-loving herbs well in Florida. These include basil, lavender, oregano, rosemary, sage, and thyme. The only potential caveat is that these popular herbs are Mediterranean and don’t like excessive moisture. For this reason, I would plant them in raised beds or containers, which tend to drain more quickly. Choose a fast-draining garden soil, like Black Gold Natural & Organic Potting Mix, for best results. Another important factor is that common perennial herbs like these require cool or cold winters to survive for years. This means that you will have to plant fresh starts a little more often.

Tropical lemongrass, which loves heat, humidity, and moisture, is an ideal herb for your climate if you like its lemony flavor (click here for a full list of lemony herbs). It should grow year-round for you. (Watch the video below about how to grow lemongrass.)

Here’s a little more about these heat-tolerant herbs.

Basil

Basil (Ocimum basilicum) is grown as an annual but will survive for several years where winters are mild. It is one of the best herbs for growing down South. (Watch the video below about growing basil in containers.)

Oregano

Oregano (Origanum vulgare, USDA Hardiness Zones 4-10) needs full sun and has low, rooting stems that spread, so be sure to give it space to grow. I recommend a low, wide pot.

Thyme

Thyme (Thymus vulgaris, USDA Hardiness Zones 5-9) is a common herb across Europe with a low, spreading, shrubby habit and pungent evergreen leaves. It requires well-drained soil and a sunny spot.

Sage

The leathery, gray, evergreen leaves of sage (Salvia officinalis, USDA Hardiness Zones 4-8) are tasty, and this hardy shrubby perennial bears pretty lavender-blue flowers in summer, which are also edible, and attract bees. Give it plenty of sun and soil with good drainage.

Lavender

Of all the lavenders, I like ‘Provence’ (Lavandula x intermedia ‘Provence’, USDA Hardiness Zones 6-9) because it is very fragrant and flowers heavily. It is a vigorous hybrid between English lavender (L. angustifolia) and Portuguese lavender (L. latifolia).  (To learn more about growing lavender, click here.)

Rosemary

In the Mediterranean, rosemary (Rosmarinus officinalis , USDA Hardiness Zones 8-10) is a favorite in landscapes and edible gardens. This sun and drought-loving herb has needle-like leaves that are resinous and fragrant. I recommend protecting is from excessive rain in Florida (click here to read more).

Happy herb gardening!

Jessie Keith

Black Gold Horticulturist

How Should I Overwinter Gladiolus in Southern Florida?

“We live in Miami and planted gladiolus bulbs this spring. They bloomed beautifully! How are we supposed to cut them, so they bloom next spring? Should we dig them up or just cut the leaves?” Question from Brenda of Miami Florida

Answer: Gladiolus hybrids will thrive year-round as perennials in your Miami garden (USDA Hardiness Zone 10), so they don’t need to be dug up in fall. Cut back the foliage as it starts to turn yellow. The plants will experience some dormancy before putting forth new foliage and then flowers.

Gladiolus species are native to Africa, Southern Europe, the Middle East, and Asia and garden hybrids are mixes of quite a few species from these areas. Where native, gladiolus undergo either a cold-season or dry-season dormant period. Because you have very little seasonal cold, the main thing that will kill your glads is excessive soil moisture during dormancy. So, make sure that their soil is fast draining and very porous. Plant them in light soil that is raised and well amended with organic matter, such as Black Gold Peat Moss. You may also want to amend further with a mineral additive, such as Gran-I-Grit or even sand, to further increase drainage. Over time, happy gladiolus can naturalize in southern gardens.

Some of my favorite glads are heirlooms with old-fashioned charm (click here for a good source). I also love the elegant Byzantine gladiolus (Gladiolus communis ssp. byzantinus), which is a species bearing long-blooming spires of purple-red summer flowers.

I hope that this information helps!

Happy gardening,

Jessie Keith