Notes of the Month Archive

December Gardening Notes of the Month

12/11/2019 by Bruce Crawford

The hustle and bustle of the Holiday Season is finally upon us! December is off to a chilly and damp start, and with the continued storms, there is little worry for newly installed plants needing water. This is the time of year to properly prepare the garden for winter, as autumn truly bids farewell and the sub-freezing temperatures of winter are just around the corner. As time permits between the cooking and the shopping, continue your notes and ledgers. On behalf of all the staff of Rutgers Gardens, a very Happy and Merry Holidays to all!

Things to do:

Cluster or spiny Mahonia foliage with a spray of pale green flower buds

Finish removing leaves from lawn areas. If possible, shred the leaves with the lawn mower and add them to perennial or annual beds as mulch. The shredded leaves that remain in the turf are actually very beneficial for the turf.
Many people think that the decaying leaves look unattractive and should be removed from beds around the home. However, the leaves, whether shredded or whole, are very important to our biosphere and should be used as mulch wherever possible!
If you have water features or ponds, keep the leaf nets over the pond at least through month’s end or until prolonged subfreezing temperatures are predicted to keep out any leaves that are still blowing about.
Decorate those containers or window boxes remaining outdoors for the winter. Evergreen boughs such as Yew, Pine, Hemlock, Southern Magnolia, fruited Holly, or Cherry Laurel can be pruned from the garden. For large pots, add containers of red stemmed Dogwoods (Cornus sericea or Cornus sanguinea) or Willow (Salix alba ‘Britzensis’) for their glowing red stems. Add some white painted birch stems, which many Garden Centers carry, in order to create an attractive winter container!
If you have recently planted an evergreen, make certain that the soil remains moist in case we have several weeks without another rainfall. A 3–4” layer of mulch over the roots certainly helps to retain the moisture and will moderate the depth to which the soil will freeze.
Rhododendrons, Holly, and other broadleaf evergreen shrubs that have been planted this fall will benefit from an application of an anti-desiccant spray. Apply during periods when the temperatures are above freezing for several hours.
Finish cutting back those perennials which have little to no winter interest and have collapsed to the ground, especially around the base of newly planted trees. The debris acts as a veil for hungry mice during the winter.
By the same token and wherever possible, leave the stems and seed heads of Black Eyed Susan (Rudbeckia), Cup Flower (Silphium), Purple Cone Flower (Echinacea) and similar flowers standing for the winter, since they provide food for the birds and overwintering habitat for native pollinators and beneficial insects!
Finish digging up Canna and Banana tubers, letting the soil dry so it can be knocked off, and then wrap and store tubers in a cool basement.
Finish gathering seed from various annuals that are not cultivars and which will come true from seed. Dry and place in labeled packets for sowing come spring!
Remove the old foliage from Bearded Iris, since egg masses from the Iris Borer overwinter on this year’s (or when they emerge, the previous year’s) foliage.
Consider edging bedlines if the ground is not frozen and time avails, as it will be one less item to consider come the spring! Do not dig the edge of the bed too deep, as lawnmower wheels are likely to fall into the trench and scalp the lawn.
Pot up daffodils, tulips, or minor bulbs into shallow pots and place them in the back of an unheated garage for the winter. Water when the soil appears dry. As the shoots begin to appear in February, place them in a sunny but cool window (hopefully in the garage). They will provide nice early color on the kitchen table in March or for outdoor containers in March, April, and May.
For Tea Roses, mulch the graft union with soil, leaves, or shredded bark after the soil has started to freeze. This will ensure that the named selection that has been budded onto a rootstock will not perish during the winter. It is often beneficial to partially prune Tea Roses back to reduce any potential wobbling due to winter winds. Complete the pruning come spring.
Winterize lawn mowers and other gas-powered equipment. This entails cleaning or replacing the filters and amending the fuel with an additive that will prevent it from becoming more viscous and potentially blocking fuel lines next season.
If there is access to composted or even fresh horse or cow manure, it can be spread now in the annual beds (not vegetable or perennial). Shredded leaves can be spread as mulch for vegetable gardens if there was not sufficient time to sow a cover crop, as it adds organic matter back into the soil.
Evaluate the Garden to see if it is in need of additional December flowering or fruiting cheer! Plants like Mahonia x ‘Charity’ (above right, photo taken on November 23, 2019), Aster carolinianus, and Hamamelis virigniana are presently in full bud or bloom and Ilex verticillata is full of glorious red, yellow, or orange fruit, depending upon the cultivar!

August Gardening Notes of the Month

08/01/2019 by Bruce Crawford

To me, August is the month that epitomizes summer. The days remain long, with the daytime chant of the cicadas and the evening chorus of the crickets. Fortunately, July provided more than adequate rainfall, so most of the plants do not look exceptionally tired from the heat. August typically has many humid days, but the temperatures are usually in the 80s, which is good for both the plants and the gardener! Remember to get outside during the cool of the morning or evening, use sunscreen, and continue to take good notes of your endeavors.

Things to do:

tall spike of small velvety purple buds with tubular purple flowers

Continue to cut the lawn, as growth and rainfall permit. Maintain a higher cutting height of 3”+ to reduce the stress on the turf.
The third and fourth weeks of August are the ideal time for reseeding or seeding new turf areas. The evening dew becomes heavier and helps to ensure proper growth and the warm soils allow proper root development before winter. Supplemental irrigation will be necessary if rainfall is light.
Make certain that plantings from this spring—as well as trees planted last year—continue to receive weekly irrigation during periods without rainfall. Remember, for a newly installed tree, every inch of caliper size (the diameter of the trunk 6” above the soil), the tree will require 1 year of additional care and watering. Hence, a tree with a 3” caliper will require 3 years of care.
Many annuals in containers may begin to look tired. For some, a light pruning with a weekly fertilizing and daily watering will breathe in new life. For others, it is simply time for replacement. For autumn, consider Salvia leucantha (Mexican Bush Sage, pictured at right) and Leonotis leonurus (Lion’s Ear) as alternatives to the garden “Mum.”
Although frost is still 2 months away, at month’s end you may wish to start taking cuttings of some annuals for rooting, potting, and overwintering for next year’s garden. If your rooting efforts fail, there is still plenty of time to take new cuttings.
Gather and save seeds of various non-hybrid annuals for seeding next spring.
Bush beans, peas, or other crops that have finished producing should be removed, the soil amended with compost, and the area replanted with a crop that will mature within 70 days or by October 15, the first average date for frost in NJ. A friend of the Gardens, Bob Mellert, mentioned that the days to maturity on seed packets should be multiplied by 1.5 to account for the slower growth time with the shortening days as compared to spring. Suggestions for 2^nd crops include:

Leaf Crops
Lettuce
Mache (like lettuce)
Mesclun Mixes
Pak Choi
Salad Greens
Spinach
Chard
Kale
Cabbage

Root Crops
Beets
Carrots
Fennel (bulbing)
Scallions
Kohlrabi
Leeks
Radishes

Other
Broccoli Raab
Broccoli
Peas

The length of harvest time for the crops listed above can be extended by erecting low tunnels in October, to mitigate any of the earlier frosts. You may wish to look into making or buying the hoops and the Agribon® row cover fabric that is used to cover the tunnels now, so you will not be rushed come October.
Squash plants may be wilting from squash borer. If so, discard the plant (best placed in garbage to remove the borer and any eggs) and plant one of the crops mentioned above.
Near the end of August, leafy crops such as Arugula, Spinach, and Lettuce can be planted, as the evening temperatures consistently drop into the 60s and upper 50s.
August is the time to get your orders in for planting Garlic this fall!
Resist the urge to vigorously prune shrubs and trees. Heavy pruning during August and September will result in a vigorous production of new shoots that will not become “hardened off” by the first frost, resulting in not only their death, but potentially the death of the plant! Removal of broken branches or light pruning/shaping is still healthy for the plant.
Many tree limbs will gradually hang down lower following the flush of new growth. Removing the lowest tier of branches on a shade or small tree during August often makes the Garden look more open and able to “breathe” again. It also allows more light to reach the plants or turf grass beneath the tree.
Late August is an ideal time to plant new perennials, shrubs and evergreens in the garden, as the soil is warm and root growth is rapid!
Try to keep up with the weeding, especially as the summer bloomers are starting to set seed and we have had ample rain for the weeds to grow. Remember, if the plant goes to seed, the average life span of a seed is 7 years!
Continue to deadhead most perennials, roses, and annuals to promote new flowers. For some, such as Echinacea and Rudbeckia, you may wish to leave the seed heads, since they are a food source for Goldfinches.
Cut back the predominantly brown Bearded Iris foliage and inspect for borer damage in the rhizome. If the clump is large and root bound, lift and split the rhizome mass apart such that one fan of foliage has an accompanying 3-4” section of the rhizome (horizontal stem). Set the pieces out in the sun for a few days, allowing the wounds to callous slightly and replant, such that the top half of the rhizome remains exposed and uncovered by soil. August is also the month to separate old Peony clumps, but be careful to leave the growth buds of the Peonies at or near the surface to ensure blossom production in the years to come. If the buds are planted too deep, the plants will fail to bloom. The peony foliage will wilt following division, but the plant will be perfectly fine come spring. Most Peonies can last 20-30 years before requiring division, so if your plant is still providing ample bloom, no division is necessary!
Bulb orders should be placed for September or October delivery. If you are interested in any of the autumn blooming Cyclamen, Crocus, or Colchicum, early August is the time to place your order for a September delivery!

July Gardening Notes of the Month

07/01/2019 by Bruce Crawford

Finally, the hazy, lazy days of summer have arrived—something many of us longed for during the long, cold and damp spring! The temperatures are warm, the sun is high in the sky, and the rain has fortunately slowed down but is still ample! The heat and humidity have certainly returned too, so try to garden during the cooler temperatures of the early mornings and evenings. Keep records on daily temperatures and rainfall, since summer’s heat and warm nighttime temperatures impact a plant as much as winter’s cold. If you live close to Rutgers Gardens, you can also look at “Rutgers Weather,” which has a summary of the weather conditions in Rutgers Gardens—it is almost like being here! Also, remember to wear a big hat, apply the sunscreen, and drink plenty of water while you garden!

Things to do:

Close up of purple and green striped leaves of Persian Shield plant, Strobilanthes

Weed and fertilize your containers. Water as needed, which is usually once per day. The plants are now beginning to approach their mature size, and it is important to keep them well fed and hydrated. If you used slow release fertilizer pellets in your containers, you may wish to consider a reapplication near month’s end, since most fertilizers only last 2 or 3 months. For heavy feeders, like Brugmansia, you should supplement slow release feed with liquid fertilizer—the slow release granules do not release the nutrients at a sufficient rate to support blooming.
Some annuals, such as Coleus, Plectranthus, and Persian Shield (Strobilanthes) would benefit from an occasional pinching of the tips, allowing lower buds to break dormancy and grow (as seen at right). This allows the plants to become denser and prevents them from getting straggly or “eating” the neighboring plants.
Hanging baskets should receive a serious cutback in order to renew the plants for a late-July through September display.
Irrigate perennial and annual gardens for long periods, ensuring a deep penetration of water into the soil, should rainfall be light during that week.
For turf grass, raise the cutting height to 3” during these hotter and drier months to reduce plant stress. If you irrigate, as with perennials, do so for extended periods during the early morning to encourage deeper root growth. Try not to water in the evening, since that will promote various fungal problems. Avoid fertilizing turf during July and early August as that will necessitate more irrigation.
For roses, deadhead, give them a light feeding and remove any leaves from the plant or on the ground that have blackspot, as this will help to reduce future outbreaks.
Any Japanese Beetles on roses or other plants can be destroyed by flicking them into soapy water.
Some perennials can be lightly trimmed, such as catnip (Nepeta faassenii) and early blooming salvias (Salvia nemerosa). I leave the dried flowers of yarrow (Achillea) and astilbe on the plant, as they are effective in fall and winter. Early July is the latest time to pinch back unruly Asters and Chrysanthemums, since pinching any later will push bloom time late into the fall.
Weed and mulch. With the rain and heat, there is an endless growth of weeds this year. It is best to get them young before they become too noticeable or the root systems become too established. Mulch reduces watering and weeds!
Peas, radishes, lettuce, spinach, and other cool season crops need to be composted and replaced by beans, beets, or any 80-day-to-maturity crop. Thin carrots to roughly 1” apart and beets to 2”.
At this point summer squash and cucumbers are beginning to come of size; harvest them small (4-6”) and frequently to ensure continued yields and tenderness. If you planted potatoes, they can also be harvested starting in mid-July. A second crop of cucumbers can be planted now to replace those planted earlier that will begin to loose vigor come late August and September.
Check parsley for Black Swallowtail Butterfly eggs or caterpillars.
If your zucchini squash get borers early in the season and collapse, and you still wish to grow squash in that location for this year, consider planting some of the scallop squash (patty pan type) for an autumn harvest. They come in solid white, golden, and a combination of white and green striped, which will add color to the Thanksgiving table as well!

close up of twine tied to a bamboo pole to support tomato plants

When watering tomatoes, make certain that the fruit remains dry in order to reduce the occurrence of blossom end rot. Keep the tomatoes staked (as seen at right and below). By positioning poles along a row of tomatoes and holding the tomatoes upright between two strings, the fruits can be kept off the ground, air can circulate through the plant (reducing disease risks), and ripening fruit is better seen. A close-up of how the plants are held is pictured below. Contact with the ground can also promote blossom end rot and other decay problems. Yellowing of the lowest leaves on the stems of tomatoes is an indication of Early Blight. It is best to remove these lower leaves, such that there is no contact with the soil, thus the threat in the future.

long row of tomato plantssupported by twine and stakes

Provide a light pruning and training of rampant growing wisteria stems, stray stems of clematis, and other vines. A heavy pruning will invigorate excessive vegetative growth and less flowering buds.
Prune watersprouts and suckers on small trees and large shrubs before they become too large and begin to deform the plant. With young ornamental or small trees, you may wish to prune off the lowest hanging branches, as they will continue to droop lower and shade out any plantings beneath. Remember, to cut branches back to—but not into—the branch collar at the base of the branch.

June Gardening Notes of the Month

06/01/2019 by Bruce Crawford

Summer has arrived! The days are wonderfully long, rain is certainly more than ample, and the temperatures are becoming more summer-like as the month progresses. June is filled with chores that linger from spring, as well as preparations necessary for the garden to continue to thrive well into late fall. As the temperatures rise, enjoy the coolness of the early mornings and evenings for those tasks requiring the most exertion, with the heat of the day reserved for light duties. Try to water in the early morning as well, since evening watering tends to promote diseases, and evaporation is most extreme during the midday hours. Also, don’t forget your hat and sunscreen, and finally, remember to sit down with your favorite cold beverage to write in your journal and to enjoy the fruits of your efforts!

Things to do:

Flowers

Finish decorating containers and mixed borders with annuals and tropicals. Do not be bashful about using larger and bolder plants such as Banana, Canna, Alocasia, Colocasia or even some of the larger Bromeliads (as pictured at right)—they add a wonderful textural impact as well as foliage color.
Fertilize annuals with a liquid feed once per week through June to give them a good start. If you used slow release fertilizer in your containers, use a 50% dilute solution of liquid feed. During hot periods, containers may need to be watered twice per day, especially if they are in the sun and if the pots are smaller than 12”.
Weed! All of the rain from May has created abundant growth and the spring blooming weeds are about to go to seed. Remember, weed seeds last an average of 7 years!
If you have deer, apply a deer spray weekly or after a heavy rain. It is best to rotate weekly between three different types of sprays for best effects.
Deadhead May-blooming iris to reduce the occurrence of the iris borer. Study the blooms of your iris; if the blooms are few and the foliage is limp or overly dense, the plant either needs division or to be moved to a more sunny location. If it needs division, August is the best time.
Deadhead the peonies as they finish blooming and lightly fertilize repeat-blooming daylilies and roses at the end of the month for a good August/September bloom.
Resist the urge to remove the yellowing foliage of daffodils and other bulbs until it has totally turned brown. The foliage is producing the carbohydrates (or stored energy) for next year’s floral display.

Shrubs and Trees

For woody plants, pinch off most of the water sprouts that you see growing from branches or stems—typically they appear at points where they were pruned off this past winter! Removing them as they start to grow discourages future dormant bud break.
Many low-branched trees may need to have portions of the lowest branches removed, as the new growth from May and early June adds weight to the branch, causing it to droop ever lower. This is a chore that often needs to be done each year until the tree is at least 15-20 years of age and the stems are of significant size to support the added weight.

Turf

Cut turf weekly. During periods of drought, irrigate the turf for extended periods in the early morning, promoting deep root growth. As the summer heat begins, raise the cutting height to 3” to reduce the stress on the turf.

Vegetables

Harvest spinach, lettuce, radishes and arugula daily. As the days become hotter, the lettuce will become increasingly bitter and less tasty. These plants will also produce flowers or “bolt,” after which the foliage becomes extremely bitter, so it is important to harvest while the plants are smaller. Once the plants begin to bolt, remove them and plant summer squash, okra, cucumbers, pole beans, or other vegetables that will provide a yield in 65-70 days (September into October).
It is not too late to plant tomatoes. Planting in June often avoids the problems with early blight as well! If the plants are leggy, bury the stem up to the first true leaf, as the stem will produce roots and yield a sturdier plant. As the tomatoes grow, make certain that they are staked, lifting the fruit to come off the ground and reducing the chance of decay.

tomato plant with the bottom leaves pinched off the stem

For tomatoes, it is ideal to pinch off the lower shoots up to the point of the first flower cluster (pictured at right). This will allow for a more manageable plant and a more sustainable crop of fruit.
Plant eggplant, peppers, okra and other plants that prefer heat of summer.
Mulch vegetables with newsprint or cardboard, covered with straw, reducing weeds and water loss. This is ideal for heirloom tomatoes since they need consistent soil moisture in order to discourage splitting of the fruit. You can also mulch with lawn clippings provided that herbicides or insecticides were not applied to the turf.
Stop harvesting asparagus and rhubarb. They need to produce stalks and leaves of sufficient size in order to develop the energy reserves for next year’s harvest (the same reason that you do not remove bulb foliage until it has turned totally brown).
Early June is time to thin your beets to 3” apart if you wish to harvest baby beets, or 5-6” if you wish them to grow larger. Either pull out or cut off the baby foliage (should you prefer not to disturb the soil). Don’t throw away the leaves either, since they are a great addition to salads!

May Gardening Notes of the Month

05/06/2019 by Bruce Crawford

April showers, combined with slightly cooler temperatures, have provided early May with a nice assortment of spring blooming plants. Although a bit chilly for those looking forward to those 90° summer days, the cool weather will allow spring blooms to last and to be enjoyed to their fullest! May is always a hectic month, so take the time to make notes in your journal and take long evening strolls to enjoy the fruits of your labor.

Things to do:

Small seed pod underneath leaves of a plant

Prune leggy Azaleas and Rhododendrons as they finish blooming. This will improve the habit, yet still ensure proper flower bud development for next year.
By late May it will be clearly evident which parts of a plant—if not the whole plant—have died back from winter’s chill and should be removed. Hydrangea macrophylla is often a guilty suspect, as the branch tips often die back and should be removed to keep the plant looking its best.
If you have fertile soils, some perennials (such as Asters and Sedums) should be pinched in mid to late May, to prevent them from flopping later in the season.
Some plants such as Bloodroot (Sanguinaria canadensis) can be easily sown in the garden by seed. Look under the foliage for the seed pods (pictured at right) and lightly squeeze the pod. If it splits open, the seeds are ripe; spread them where you would like to add some plants!
Let bulb foliage turn yellow or tan before removing, to ensure proper bulb and flower development for next year. Do not tie it together, since that reduces the amount of surface area exposed to the sun and limits its ability to make both sugars and next year’s embryonic flowers.
For bulbs such as Eranthis (Winter Aconite), gather the seeds as the capsules ripen and start to split, and spread the seed throughout woodland areas. The same holds true for Bloodroot (Sanguinaria canadensis). Longwood Gardens has found this a far more successful method of spreading the plants about than the typical method of installing the tubers in the fall.
Bulbs such as Snowdrops (Galanthus sp.) and Snowflakes (Leucojum sp.) transplant much better if the mature clumps are split and transplanted, rather than starting with new dormant bulbs in the fall.
For a neat garden, edge those beds! For vegetable and annual gardens, turn under any manure spread or green crops seeded out last fall. Make certain the soil has drained properly before working the soil.
Plant out tender annuals after the last frost-free date in your part of the state (generally May 15^th, but it can occur later). May temperatures can fluctuate from 90° one day to 30° the next! Also, certain annuals that like it warm, such as Catharanthus (the annual Vinca) and Sweet Potato Vines should not be planted until late May or early June.
Remove the Banana and Cana roots from the basement and plant them in a sunny location in soils that are enriched with compost to help hold moisture.
The Colocasia and Alocasia roots or potted plants can be planted out in early May. They are surprisingly tolerant of cooler temperatures when young.
Thin those cool season vegetables that were directly sown during April so that they will develop more fully.
Start to plant frost-tender vegetables. For the eager, the wall of water can be used for tomatoes and other tender vegetables that are planted during the potentially cold first half of the month, although there is no harm in waiting until early June!
Cut those lawns. Remember, 2 ½–3” length is far healthier for the turf than a 2” cut. Do not remove the clippings since they release nitrogen back into the soil as they break down.
Spot treat for dandelions or any other aggressive lawn weed.
Finish mulching perennial or shrub borders during the early part of May and start to weed! Remember the average weed seed’s life is 7 years, so remove those weeds before they go to seed.
Frequently visit local garden centers as new additions are coming in weekly.
Plant sales at botanic garden occur throughout the state and are a great source for finding unique or hard to find plants—plus it supports the various gardens. If you missed the sale at Rutgers Gardens on May 10-12, 2019, we will still have plants available at the Farm Market every Friday from 11:00-5:00 and weekends at the Gift Shop!! This year, we are also having a follow-up sale on Saturday May 18, to celebrate National Public Gardens Week. Come out and enjoy the discounted prices on some fantastic plants!
Read the notes that you made this winter and last May, and reflect on how to improve the garden. It is now time to put your thoughts into action!