Frequently Asked Questions

We’re here to provide answers to you garden and plant questions. If you don’t see you question here, send it to us. We’ll be happy to provide you with and answer and add it to our FAQ list!

Can I lift it?

Plants may be heavier than you think – especially if they have a large root ball or are wet. Whether you’re moving them yourself or getting help from your landscaper, you’ll want to ensure you’ve got the lifting capacity to move your plants to the places they need to be and that the holes you dig are big enough when you get them there. Download our guidelines for the estimated weight of a variety of plants and lifting capacities for a variety of machines commonly used for such jobs. 

Can you recommend deer-resistant plants?

A number of plants are not generally eaten by deer – although if deer populations are high and food is scarce, they will eat almost anything. In general deer dislike highly-scented or prickly plants, but they will nibble on unpalatable plants located in their feeding area. Deer like Rhododendron, Taxus (yew), Thuja (arborvitae) and Cuprocyparis leylandii (Leyland cypress). Download our guide on plants less likely to be eaten by deer

Can you recommend plants for a shady spot?

All plants need a balance of light, moisture and temperature, but these needs vary. Download our guide to help you choose plants for a shady spot in your garden

Can you recommend plants for a wet spot?

All plants need a balance of light, moisture and temperature, but these needs vary. Download our guide to help you choose plants for a wet spot in your garden.

Can you recommend plants for sea and shore exposure?

Living by the ocean can be tough on plants few woody plants will survive seashore conditions. Download our guide to help you choose plants that will tolerate being on the beach or nearby areas.

Cut-and-come-again salads

Keep your lettuce and other salad leaves going all summer long. Plant densely, than rather than pulling them up, just cut the leaves you need and leave the plant to regrow.Works on pea shoots, too.

We’ve got loads of salad leaves, including certified organic seedlings, and if you’re short of space a window box of leaves is all it takes to add your own produce to your table.

Eat your blossoms

Edible flowers make a pretty addition to salads and are lovely frozen in ice cubes. Once you correctly identify the petals, why not try something from our handy list.

Get composting

When folks ask how much compost they should buy, they answer is always, “As much as your vehicle can hold!” Adding a 1-3″ layer of compost to your garden every year improves your soil enormously. Besides being a natural fertilizer that will not burn plants, it helps soil retain moisture and encourages beneficial insects and worms. Compost improves the soil structure and aeration as well, helping any soil that is too sandy or has too much clay as worms pull the compost down into the earth.

Consider making your own compost – it’s easy and a great way to cut down on your household waste by turning vegetable scraps, egg shells and boxes, fruit peel, grass clippings, leaves you rake up, newspaper and cardboard into valuable, free soil conditioner. Just mix kitchen waste and layer it into your compost heap. Adding a thick layer of grass clippings when you can helps make great compost and keeps your heap hot. If you can, add a roughly equal amount of shredded newspaper or cardboard, which will help make a give your compost a nice texture.

Then just leave it there for a six months to a year, depending on conditions and quantity (bigger heaps get hotter, so break down compost more quickly), and you’ll have compost. You can tell it’s ready to use when it is dark and crumbly and looks like the stuff you can buy in a bag.

It’s that easy, and contrary to some misconceptions, a good compost heap doesn’t smell. You don’t even need a compost bin, although they quicken the process by keeping the moisture level and temperature high. Some composters are raised on feet and enclosed with a crank handle on the side to make turning easier. Making compost directly on the ground, either in an open heap or within a bin with no bottom, will permit worms and other beneficial critters to get into the heap and help the process along.

Top tips for making even better compost include:

  • Keep a small, preferably covered, bucket in your kitchen and put kitchen waste straight into it. Empty it every couple of days, especially in hot weather. Rinse out your bucket and put that water into the heap as it helps add a little moisture to your heap.
  • Don’t use meat scraps, you might encourage unwelcome wild or doggie visitors.
  • Site your compost heap in a place that is reasonably accessible from your kitchen to make it less of a chore to empty the compost bucket. If you can, make sure it is also uphill from the place you want to use the bulk of the compost – that way your won’t have to push wheelbarrows full of heavy compost uphill.
  • If you add plants you weed out of your garden to your compost heap, try keep out the perennials and anything in seed unless your compost gets very hot or you’ll just be saving up trouble for next year – some things are better burned or thrown under shrubs or in other corners as habitat for all kinds of creatures.
  • Covering your heap, for instance with a tarpaulin, will help keep heat and moisture in, which makes for quicker, better compost.
  • Don’t let your heap dry out – if you don’t have a cover, make sure you water your heap or it won’t make compost.
  • You’ll get better compost if you turn it with a fork every few weeks, but you don’t have too, just use last year’s compost first, digging under your heap to get at the good stuff. This helps turn your compost as well to ensure it all gets nice and hot.

You can’t have too much compost, but every little bit helps, including by keeping useful stuff out of landfills.

Give your houseplants a vacation

Many houseplants enjoy a trip outdoors when the weather warms up. Out in the sunshine you may find leaves need a good clean with fresh water or a special leaf shine product. This not only perks up the look of your plants, but it helps them thrive. For heavy indoor plants that you summer outdoors, use plant trivets with four casters to make transporting them less backbreaking, or use a specially-made strap that makes lifting by two people much easier. 

Gosh it's hot!

Ellen’s top tip for cool refreshment:

Freeze mint, lemon verbena, rose petals or any of your favorite herbs in ice cubes to float in water or soda water, with or without a slice of lemon or lime. Enjoy.

We’ve prepared a list of more ideas on edible flowers you can use. 

Chilled teas made from fresh herbs make a refreshing drink, too.

We’ve got loads of herbs in a variety of sizes so you can stock up on old favorites or try something new.

Got aphids?

You can control them with a strong blast of water from the hose or with insecticidal soap. You can also wrap a wide strip of tape around your hand, sticky side out, and pat the leaves of plants infested with aphids. Concentrate on the undersides of leaves, because that’s where they like to hide.

Growing low-maintenance moss

Besides providing a tranquil and lush environment, moss highlights even the smallest of plants. Plus there’s a lot of variety. Of the more than 15,000 different species of moss worldwide, there are four types that are available commercially:

  • Haircap moss, or Polytrichum, is the tallest of the four types. 
  • Cushion moss derives its name from its round, cushionlike growth pattern. It can tolerate partial sun but prefers shade. 
  • Rockcap moss is usually found growing atop boulders. 
  • Fern moss is the most versatile of the mosses, and this low-growing type has the highest success rate when transferred.

As far as maintenance goes, all you have to do is keep your moss stand clear of leaves and debris. “One thing that works great is quarter-inch black mesh netting,” says moss enthusiast Dave Benner. “Lay it down before the leaves start to fall, and then once the leaves have fallen, you simply roll it up.”

How can I grow a long succession of blueberries?

There are many types of blueberries, each with different characteristics and fruiting times. Carefully choosing varieties can help you ensure a long crop of berries. See our guide for information on blueberry varieties and their characteristics to help you make your choices. 

How can I help protect pollinators?

This is a really important one, so we’ve got a whole page of information on protecting pollinators.

How do I force bulbs?

Beautiful bowls of blooming bulbs make great Christmas gifts and decorations for your table. Tulip, daffodil (narcissus), hyacinth, crocus, scilla, grape hyacinth, snowdrop and lily of the valley can be forced to bloom in the Winter or early Spring by mimicking Winter in your home. The process should be started 6-13 weeks before the blooms are needed. Download our guide for all the information you need to have blooming bulbs for the Winter

How do I treat black spot?

Black spot is one of the most common diseases of roses. It begins as black spots up to ½” across on upper leaf surfaces, then leaves turn yellow around the spots, then all yellow, and finally they fall off. Spots may also appear on rose canes, first purple and then turning black.

Black spot is a fungal disease and requires at least seven hours of wet conditions to infect roses. It is inhibited by temperatures above about 85 degrees F. While you may not be able to keep roses hot, keeping them dry by watering early in the day and enabling good air circulation with proper spacing in open sunshine will help minimize the disease.

Black spot overwinters in fallen leaves and infected canes, so pruning out infections and raking up leaves at the end of the season will provide an additional brake.

Any spray containing neem oil, like Bonide Rose 3-in-1 care or Serenade, will help control the disease, and both are organic.

How do I treat gray mold (Botrytis)?

Perhaps the most common disease of flowers, gray mold attacks any plant, primarily on old and dying leaves and flowers. It begins on water-soaked spots and grows into a gray, fuzzy coating. It thrives in high moisture/low temperature environments, so water early to allow foliage to dry out during the day, allow plenty of air circulation around plants and remove diseased flowers or leaves (but don’t put them on your compost heap).

Spores spread the disease, so it is important to keep water splashing to a minimum by watering near the bottom of plants or using drip irrigation.

Any spray containing neem oil, like Bonide Rose 3-in-1 care or Serenade, will help control the disease, and both are organic.

How do I treat powdery mildew?

Powdery mildew is a fungal disease that resembles a white powder on leaves, which will eventually turn yellow, then brown, then die. Although not fatal, it may weaken plants over several years.

Powdery mildew thrives in high humidity, so keeping plants well-spaced will promote air circulation and lower humidity around them. Choosing resistant varieties will also help you avoid problems.

You can treat the disease with horticultural oil or baking soda (make a spray from 1 Tbs baking soda and ½ tsp liquid soap to one gallon of water). Begin treatment as soon as you notice the onset of the disease, often in late June or July, and then every two weeks after. If you want to purchase a ready-made treatment, we highly recommend either Bonide Rose Rx 3-in-1 or Serenade Disease Control – both are organic and effective.

How many plants do I need?

It can be hard to know how many plants to buy to ensure the space in your garden looks its best. Below is a handy table to help you figure it all out. Once you know the size of the space you want to fill, our downloadable guide helps you calculate how many plants you need depending on their mature size.

How to I plant my new trees, shrub or other plant?

Please download our planting guidelines for all the advice you need to give your new trees, plants and shrubs the best possible start. 

Perk up your plants

Coffee grounds contain some major nutrients (nitrogen, phosphorus, and potassium), as well as some micronutrients, so put them to work in your garden. Allow them to dry and then spread them around the base of plants. Coffee grounds may benefit acid-loving plants, and they also appear to have some negative effect on weed growth, slugs and snails, which is doubly helpful for lettuces. Ask your local coffee shop if you can take away their used grounds – less waste for them and free stuff for you.

Pollination and seed saving - Hybrids vs heirlooms


Open-pollinated varieties, often labelled “heirloom” or given no special mark, are standard, consistent varieties that will produce not only food for you, but seed you can save for next year. Most lettuce, bean and pea varieties for home gardeners are open-pollinated.


Hybrid varieties, often marked “F1”, are very uniform and reliable. However hybrids do not produce reliable seed, so new seeds must be purchased from seed companies or nurseries, unless you want to gamble and see what offspring your home-saved hybrid seeds will produce, if any. Most cabbages, broccoli, cucumbers, melons and Brussels sprouts are hybrids, and hybrid summer squashes, cucumbers, melons, corn and carrots dominate the garden seed market. 

Removing salt deposits from clay pots

To remove the salt deposits that form on clay pots, combine equal parts white vinegar, rubbing alcohol and water in a spray bottle. Apply the mixture to the pot and scrub with a plastic brush. Let the pot dry before you plant anything in it.

Understanding fruit tree pollination


While some varieties are self-fertile, most fruit trees are self-sterile, meaning they need to be fertilized pollen from the blossom of another variety to produce fruit. These co-pollinators must from compatible varieties that bloom at the same time in order for the pollen to do its work. The pollen must also be carried from one variety to the other, either by the wind or by insects (like wasps, flies and bees), so the trees must be planted no more than 50-100’ apart.

Some apple varieties need co-pollinators, but their own pollen is sterile, so they do not return the favour to other varieties. These include: Jonagold, Winesap, Spigold, Baldwin, Tompkins County King, Roxbury Russet, Summer Rambo, Gravenstein, Rhode Island Greening, Mutsu and Red Stayman Winesap.


Most are self-pollinating, as are some sweet cherries.


There are a variety of ways to determine which varieties would make good pollinating partners, including:

  • Checking the tags on the trees you are considering
  • Asking staff here at Plants Unlimited, who will be more than happy to help
  • Checking with other experts, like the University of Missouri, which has a helpful chart online showing which varieties work well together, as well as lots of other interesting information.

Low yields or no fruit is probably the result of poor pollination or frost on blossom.

Understanding plant hardiness zones

Hardiness zones are determined by the US Department of Agriculture and based on regional temperature averages, giving a good general guide to the lowest or highest possible temperature in the area during a normal year. Knowing the zone in which you garden can help you identify plants that will thrive, or which you may need to give a little extra support or later planting. You can learn more about zones here.

We aim to provide information about the zones assigned to each of our plants, but it’s a big job, so please be patient while we get our new website up and running. You can always call us for information about any plant – we’re here to help. 

Understanding tomato types - Determinate vs Indeterminate


Also called bush tomatoes, these varieties are bred to grow to a compact height (approximately 4′). They stop growing when fruit sets on the terminal or top bud, ripen all their crop at or near the same time (usually over a 2 week period), and then die.They may require a limited amount of caging and/or staking for support, should NOT be pruned or “suckered” as it severely reduces the crop. They will perform relatively well in containers (minimum size of 5-6 gallon).


Also called vining tomatoes, these varieties will grow and produce fruit until killed by frost and can reach heights of up to 10′, although 6′ is considered the norm. They will bloom, set new fruit and ripen fruit all continuously throughout the growing season. They require substantial caging and/or staking for support and pruning and the removal of suckers is practiced by many but is not mandatory. The need for it and advisability of doing it varies from region to region.

Experiment and see which works best for you. The need for substantial support and the size of the plants means indeterminate varieties are not usually recommended as container plants.

Understanding winterberry pollination

Winterberry (Ilex verticillata) has both male and female plants. Only female flowers fertilized by pollen from the correct male will produce the plant’s signature red berries.

Download our guide to get information on winterberry co-pollinators and pollination times for popular varieties.

Water right

House plants can die as easily from overwatering as underwatering, so make sure you give your plants what they need. Giving them a top dressing of fresh soil will perk them up as well. We have an extensive range of plant feeds to give your plants a tonic when you water.

Welcoming hummingbirds to your garden

Check out our Hummingbirds page. 

What flowers are best for cutting?

Download our guide for our top flower cutting tips

What flowers are best for drying?

Download our guide for our top flower drying tips

What plants are native to New England?

Native plants are an important part of creating a healthy garden and contributing to a healthy local environment. They support indigenous wildlife, including pollinators, often hosting hundreds of species per plants (as do oaks, for instance). Download our guide for a list of groundcover, trees and shrubs native to our area

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Rockport, ME 04856

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